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Nombre minimum de suppressions et d'insertions pour transformer une chaîne en une autre

Étant donné deux chaînes s1 et s2 . La tâche est de supprimer/supprimer et insérer le nombre minimum de caractères depuis s1 pour le transformer en s2 . Il pourrait être possible que le même personnage doit être retiré/supprimé d’un point de s1 et inséré à un autre endroit.

Exemple 1 :  

Saisir: s1 = 'tas' s2 =
Sortir: 3
Explication: Suppression minimale = 2 et insertion minimale = 1
p et h sont supprimés du tas puis p est inséré au début. Une chose à noter, même si p était requis, il a d'abord été retiré/supprimé de sa position, puis inséré dans une autre position. Ainsi p contribue un au nombre de suppressions et un au nombre d’insertions.



Saisir: s1 = 'geeksforgeeks' s2 = 'geeks'
Sortir: 8
Explication: 8 suppressions, c'est-à-dire supprimer tous les caractères de la chaîne 'forgeeks'.

Table des matières

Utilisation de la récursivité - O(2^n) Time et O(n) Space

Une approche simple pour résoudre le problème consiste à générer tous sous-séquences de s1 et pour chaque sous-séquence calculer le minimum suppressions et insertions nécessaires pour le transformer en s2. Une approche efficace utilise le concept de sous-séquence commune la plus longue (LCS) pour trouver la longueur du LCS le plus long. Une fois que nous avons le LCS de deux chaînes, nous pouvons trouver Insertion minimale et Suppressions pour convertir s1 en s2.

  • À minimiser les suppressions il suffit de supprimer des caractères de s1 qui ne font pas partie du sous-séquence commune la plus longue (LCS) avec s2 . Ceci peut être déterminé par soustraire le Longueur du LCS de la longueur de s1 . Ainsi le nombre minimum de suppressions est :
    minDeletions = longueur de s1 - longueur LCS.
  • De même pour minimiser les insertions il suffit d'insérer des caractères de s2 dans s1 qui ne font pas partie du LCS. Ceci peut être déterminé par soustraire le Longueur du LCS de la longueur de s2 . Le nombre minimum d'insertions est donc :
    minInsertions = longueur de s2 - longueur LCS.
C++
// C++ program to find the minimum number of insertion and deletion // using recursion. #include    using namespace std; int lcs(string &s1 string &s2 int m int n) {    // Base case: If either string is empty  // the LCS length is 0  if (m == 0 || n == 0)  return 0;  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1])  // Include the matching character in LCS and   // recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  else  // If the last characters do not match   // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return max(lcs(s1 s2 m n - 1) lcs(s1 s2 m - 1 n)); } int minOperations(string s1 string s2) {  int m = s1.size();  int n = s2.size();  // the length of the LCS for s1[0..m-1]  // and s2[0..n-1]  int len = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum number of insertions and // deletions using recursion. class GfG {    static int lcs(String s1 String s2 int m int n) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0) {  return 0;  }  // If the last characters of both substrings match  if (s1.charAt(m - 1) == s2.charAt(n - 1)) {  // Include the matching character in LCS  // and recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  }  }  static int minOperations(String s1 String s2) {  int m = s1.length();  int n = s2.length();  // the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int len = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s2  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {  String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum number of insertions # and deletions using recursion def lcs(s1 s2 m n): # Base case: If either string is empty # the LCS length is 0 if m == 0 or n == 0: return 0 # If the last characters of both substrings match if s1[m - 1] == s2[n - 1]: # Include the matching character in LCS and  # recurse for remaining substrings return 1 + lcs(s1 s2 m - 1 n - 1) else: # If the last characters do not match  # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 return max(lcs(s1 s2 m n - 1) lcs(s1 s2 m - 1 n)) def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of LCS for s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2 m n) # Characters to delete from str1 minDeletions = m - lengthLcs # Characters to insert into str1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions if __name__ == '__main__': s1 = 'AGGTAB' s2 = 'GXTXAYB' result = minOperations(s1 s2) print(result) 
C#
// C# program to find the minimum number of insertions and // deletions using recursion. using System; class GfG {  static int lcs(string s1 string s2 int m int n) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0)  return 0;  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1]) {    // Include the matching character in LCS  // and recurse for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.Max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  }  }  static int minOperations(string s1 string s2) {  int m = s1.Length;  int n = s2.Length;  // the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int lengthLcs = lcs(s1 s2 m n);  // Characters to delete from s1  int minDeletions = m - lengthLcs;  // Characters to insert into s2  int minInsertions = n - lengthLcs;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main(string[] args) {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int result = minOperations(s1 s2);  Console.WriteLine(result);  } } 
JavaScript
// JavaScript program to find the minimum number of // insertions and deletions using recursion function lcs(s1 s2 m n) {  // Base case: If either string is empty the LCS length  // is 0  if (m === 0 || n === 0) {  return 0;  }  // If the last characters of both substrings match  if (s1[m - 1] === s2[n - 1]) {    // Include the matching character in LCS and recurse  // for remaining substrings  return 1 + lcs(s1 s2 m - 1 n - 1);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return Math.max(lcs(s1 s2 m n - 1)  lcs(s1 s2 m - 1 n));  } } function minOperations(s1 s2) {  const m = s1.length;  const n = s2.length;  // Length of the LCS  const len = lcs(s1 s2 m n);  // Characters to delete from s1  const minDeletions = m - len;  // Characters to insert into s1  const minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

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5

Utilisation du DP descendant (mémoisation) - O(n^2) Temps et O(n^2) Espace

Dans cette approche, nous appliquons mémorisation pour stocker les résultats des sous-problèmes qui se chevauchent tout en trouvant la sous-séquence commune la plus longue (LCS). UN tableau 2D note est utilisé pour sauvegarder le LCS longueurs pour différentes sous-chaînes des deux chaînes d'entrée garantissant que chaque sous-problème n'est résolu qu'une seule fois.
Cette méthode est similaire à Sous-séquence commune la plus longue (LCS) problème d'utilisation de la mémorisation.

C++
// C++ program to find the minimum of insertion and deletion // using memoization. #include    #include  using namespace std; int lcs(string &s1 string &s2 int m int n   vector<vector<int>> &memo) {    // Base case: If either string is empty the LCS length is 0  if (m == 0 || n == 0)  return 0;  // If the value is already computed return  // it from the memo array  if(memo[m][n]!=-1)  return memo[m][n];    // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1])    // Include the matching character in LCS and recurse for  // remaining substrings  return memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  else    // If the last characters do not match find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  return memo[m][n] = max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo)); } int minOperations(string s1 string s2) {    int m = s1.size();   int n = s2.size();     // Initialize the memoization array with -1.  vector<vector<int>> memo = vector<vector<int>>  (m+1vector<int>(n+1-1));    // the length of the LCS for   // s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and deletion // using memoization. class GfG {  static int lcs(String s1 String s2 int m int n int[][] memo) {    // Base case: If either string is empty   // the LCS length is 0  if (m == 0 || n == 0) {   return 0;  }  // If the value is already computed return it  // from the memo array  if (memo[m][n] != -1) {  return memo[m][n];  }  // If the last characters of both substrings match  if (s1.charAt(m - 1) == s2.charAt(n - 1)) {  // Include the matching character in LCS and recurse for  // remaining substrings  memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m][n] = Math.max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }  return memo[m][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();   int n = s2.length();   // Initialize the memoization array with -1   // (indicating uncalculated values)  int[][] memo = new int[m + 1][n + 1];  for (int i = 0; i <= m; i++) {  for (int j = 0; j <= n; j++) {  memo[i][j] = -1;  }  }  // the length of LCS for s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  static void main(String[] args) {    String s1 = 'AGGTAB';   String s2 = 'GXTXAYB';   int res = minOperations(s1 s2);   System.out.println(res);   } } 
Python
# Python program to find the minimum number of insertions and  # deletions using memoization def lcs(s1 s2 m n memo): # Base case: If either string is empty the LCS length is 0 if m == 0 or n == 0: return 0 # If the value is already computed  # return it from the memo array if memo[m][n] != -1: return memo[m][n] # If the last characters of both substrings match if s1[m - 1] == s2[n - 1]: # Include the matching character in LCS and  # recurse for remaining substrings memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo) else: # If the last characters do not match  # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 memo[m][n] = max(lcs(s1 s2 m n - 1 memo) lcs(s1 s2 m - 1 n memo)) # Return the computed value return memo[m][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # Initialize the memoization array with -1 # (indicating uncalculated values) memo = [[-1 for _ in range(n + 1)] for _ in range(m + 1)] # Calculate the length of LCS for s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2 m n memo) # Characters to delete from s1 minDeletions = m - lengthLcs # Characters to insert into s1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions if __name__ == '__main__': s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using memoization. using System; class GfG {    static int lcs(string s1 string s2 int m int n  int[ ] memo) {    // Base case: If either string is empty the LCS  // length is 0  if (m == 0 || n == 0) {  return 0;  }  // If the value is already computed return it from  // the memo array  if (memo[m n] != -1) {  return memo[m n];  }  // If the last characters of both substrings match  if (s1[m - 1] == s2[n - 1]) {    // Include the matching character in LCS and  // recurse for remaining substrings  memo[m n]  = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m n]  = Math.Max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }  // Return the computed value  return memo[m n];  }    static int minOperations(string s1 string s2) {    int m = s1.Length;   int n = s2.Length;   // Initialize the memoization array with -1  // (indicating uncalculated values)  int[ ] memo = new int[m + 1 n + 1];  for (int i = 0; i <= m; i++) {  for (int j = 0; j <= n; j++) {  memo[i j] = -1;  }  }  // Calculate the length of LCS for s1[0..m-1] and  // s2[0..n-1]  int lengthLcs = lcs(s1 s2 m n memo);  // Characters to delete from s1  int minDeletions = m - lengthLcs;  // Characters to insert into s1  int minInsertions = n - lengthLcs;  // Total operations needed  return minDeletions + minInsertions;  }    static void Main(string[] args) {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);   } } 
JavaScript
// JavaScript program to find the minimum number of // insertions and deletions using memoization function lcs(s1 s2 m n memo) {  // Base case: If either string is empty the LCS length  // is 0  if (m === 0 || n === 0) {  return 0;  }  // If the value is already computed return it from the  // memo array  if (memo[m][n] !== -1) {  return memo[m][n];  }  // If the last characters of both substrings match  if (s1[m - 1] === s2[n - 1]) {    // Include the matching character in LCS and recurse  // for remaining substrings  memo[m][n] = 1 + lcs(s1 s2 m - 1 n - 1 memo);  }  else {    // If the last characters do not match find the  // maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  memo[m][n] = Math.max(lcs(s1 s2 m n - 1 memo)  lcs(s1 s2 m - 1 n memo));  }    return memo[m][n]; } function minOperations(s1 s2){  const m = s1.length;  const n = s2.length;  // Initialize the memoization array with -1 (indicating  // uncalculated values)  const memo = Array.from({length : m + 1}  () => Array(n + 1).fill(-1));  // Calculate the length of LCS for s1[0..m-1] and  // s2[0..n-1]  const len = lcs(s1 s2 m n memo);  // Characters to delete from s1  const minDeletions = m - len;  // Characters to insert into s1  const minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

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5

Utilisation de DP ascendante (tabulation) - O (n ^ 2) Temps et O (n ^ 2) Espace

L'approche est similaire à celle le précédent juste au lieu de résoudre le problème récursivement nous de manière itérative construire la solution en calculant en de bas en haut manière. Nous maintenons un Tableau dp[][] 2D tel que dp[i][j] stocke le Sous-séquence commune la plus longue (LCS) pour le sous-problème (i j) .
Cette approche est similaire à la découverte LCS de manière ascendante .

C++
// C++ program to find the minimum of insertion and deletion // using tabulation. #include    #include  using namespace std;   int lcs(string &s1 string &s2) {    int m = s1.size();  int n = s2.size();  // Initializing a matrix of size (m+1)*(n+1)  vector<vector<int>> dp(m + 1 vector<int>(n + 1 0));  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1[i - 1] == s2[j - 1])  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j] = max(dp[i - 1][j] dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m][n]; } int minOperations(string s1 string s2) {    int m = s1.size();  int n = s2.size();  // the length of the LCS for  // s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and // deletion using tabulation. class GfG {    static int lcs(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // Initializing a matrix of size (m+1)*(n+1)  int[][] dp = new int[m + 1][n + 1];  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1.charAt(i - 1) == s2.charAt(j - 1))  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j] = Math.max(dp[i - 1][j]  dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // the length of the LCS for s1[0..m-1] and  // str2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {    String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum of insertion and deletion # using tabulation. def lcs(s1 s2): m = len(s1) n = len(s2) # Initializing a matrix of size (m+1)*(n+1) dp = [[0] * (n + 1) for _ in range(m + 1)] # Building dp[m+1][n+1] in bottom-up fashion for i in range(1 m + 1): for j in range(1 n + 1): if s1[i - 1] == s2[j - 1]: dp[i][j] = dp[i - 1][j - 1] + 1 else: dp[i][j] = max(dp[i - 1][j] dp[i][j - 1]) # dp[m][n] contains length of LCS for # s1[0..m-1] and s2[0..n-1] return dp[m][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of the LCS for  # s1[0..m-1] and s2[0..n-1] lengthLcs = lcs(s1 s2) # Characters to delete from s1 minDeletions = m - lengthLcs # Characters to insert into s1 minInsertions = n - lengthLcs # Total operations needed return minDeletions + minInsertions s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using tabulation. using System; class GfG {    static int Lcs(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // Initializing a matrix of size (m+1)*(n+1)  int[ ] dp = new int[m + 1 n + 1];  // Building dp[m+1][n+1] in bottom-up fashion  for (int i = 1; i <= m; ++i) {  for (int j = 1; j <= n; ++j) {  if (s1[i - 1] == s2[j - 1])  dp[i j] = dp[i - 1 j - 1] + 1;  else  dp[i j] = Math.Max(dp[i - 1 j]  dp[i j - 1]);  }  }  // dp[m n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m n];  }  static int minOperations(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int len = Lcs(s1 s2);  // Characters to delete from str1  int minDeletions = m - len;  // Characters to insert into str1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main() {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);  } } 
JavaScript
// JavaScript program to find the minimum of insertion and // deletion using tabulation. function lcs(s1 s2) {  let m = s1.length;  let n = s2.length;  // Initializing a matrix of size (m+1)*(n+1)  let dp = Array(m + 1).fill().map(  () => Array(n + 1).fill(0));  // Building dp[m+1][n+1] in bottom-up fashion  for (let i = 1; i <= m; ++i) {  for (let j = 1; j <= n; ++j) {  if (s1[i - 1] === s2[j - 1])  dp[i][j] = dp[i - 1][j - 1] + 1;  else  dp[i][j]  = Math.max(dp[i - 1][j] dp[i][j - 1]);  }  }  // dp[m][n] contains length of LCS for s1[0..m-1] and  // s2[0..n-1]  return dp[m][n]; } function minOperations(s1 s2) {  let m = s1.length;  let n = s2.length;  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  let len = lcs(s1 s2);  // Characters to delete from s1  let minDeletions = m - len;  // Characters to insert into s1  let minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions; } let s1 = 'AGGTAB'; let s2 = 'GXTXAYB'; let res = minOperations(s1 s2); console.log(res); 

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5

Utilisation du DP ascendant (optimisation de l'espace) – temps O(n^2) et espace O(n)

Dans l'approche précédente, le sous-séquence commune la plus longue (LCS) l'algorithme utilise O(n*n) espace pour stocker l'ensemble table de dp . Cependant, puisque chaque valeur dans dp[i][j ] ne dépend que du ligne actuelle et le ligne précédente nous n'avons pas besoin de stocker la table entière. Cela peut être optimisé en stockant uniquement les lignes actuelles et précédentes. Pour plus de détails, reportez-vous à Une solution de LCS optimisée pour l'espace .

C++
// C++ program to find the minimum of insertion and deletion // using space optimized. #include    using namespace std; int lcs(string &s1 string &s2) {    int m = s1.length() n = s2.length();  vector<vector<int>> dp(2 vector<int>(n + 1));  for (int i = 0; i <= m; i++) {  // Compute current binary index. If i is even  // then curr = 0 else 1  bool curr = i & 1;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  else if (s1[i - 1] == s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  else  dp[curr][j] = max(dp[1 - curr][j] dp[curr][j - 1]);  }  }  return dp[m & 1][n]; } int minOperations(string s1 string s2) {  int m = s1.size();  int n = s2.size();  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  int total = minDeletions + minInsertions;  return total; } int main() {  string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  cout << res;  return 0; } 
Java
// Java program to find the minimum of insertion and // deletion using space optimized. class GfG {    static int lcs(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // Initializing a 2D array with size (2) x (n + 1)  int[][] dp = new int[2][n + 1];  for (int i = 0; i <= m; i++) {  // Compute current binary index. If i is even  // then curr = 0 else 1  int curr = i % 2;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column  // with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  else if (s1.charAt(i - 1)  == s2.charAt(j - 1))  dp[curr][j] = dp[1 - curr][j - 1] + 1;  else  dp[curr][j] = Math.max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  return dp[m % 2][n];  }  static int minOperations(String s1 String s2) {    int m = s1.length();  int n = s2.length();  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int len = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - len;  // Characters to insert into s1  int minInsertions = n - len;  // Total operations needed  return minDeletions + minInsertions;  }  public static void main(String[] args) {    String s1 = 'AGGTAB';  String s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  System.out.println(res);  } } 
Python
# Python program to find the minimum of insertion and deletion # using space optimized. def lcs(s1 s2): m = len(s1) n = len(s2) # Initializing a matrix of size (2)*(n+1) dp = [[0] * (n + 1) for _ in range(2)] for i in range(m + 1): # Compute current binary index. If i is even # then curr = 0 else 1 curr = i % 2 for j in range(n + 1): # Initialize first row and first column with 0 if i == 0 or j == 0: dp[curr][j] = 0 # If the last characters of both substrings match elif s1[i - 1] == s2[j - 1]: dp[curr][j] = dp[1 - curr][j - 1] + 1 # If the last characters do not match # find the maximum LCS length by: # 1. Excluding the last character of s1 # 2. Excluding the last character of s2 else: dp[curr][j] = max(dp[1 - curr][j] dp[curr][j - 1]) # dp[m & 1][n] contains length of LCS for s1[0..m-1] and s2[0..n-1] return dp[m % 2][n] def minOperations(s1 s2): m = len(s1) n = len(s2) # the length of the LCS for s1[0..m-1] and s2[0..n-1] length = lcs(s1 s2) # Characters to delete from s1 minDeletions = m - length # Characters to insert into s1 minInsertions = n - length # Total operations needed return minDeletions + minInsertions s1 = 'AGGTAB' s2 = 'GXTXAYB' res = minOperations(s1 s2) print(res) 
C#
// C# program to find the minimum of insertion and deletion // using space optimized. using System; class GfG {  static int lcs(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // Initializing a matrix of size (2)*(n+1)  int[][] dp = new int[2][];  dp[0] = new int[n + 1];  dp[1] = new int[n + 1];  for (int i = 0; i <= m; i++) {    // Compute current binary index. If i is even  // then curr = 0 else 1  int curr = i % 2;  for (int j = 0; j <= n; j++) {    // Initialize first row and first column  // with 0  if (i == 0 || j == 0)  dp[curr][j] = 0;  // If the last characters of both substrings  // match  else if (s1[i - 1] == s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  else  dp[curr][j] = Math.Max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  // dp[m & 1][n] contains length of LCS for  // s1[0..m-1] and s2[0..n-1]  return dp[m % 2][n];  }  static int minOperations(string s1 string s2) {    int m = s1.Length;  int n = s2.Length;  // the length of the LCS for s1[0..m-1] and  // s2[0..n-1]  int length = lcs(s1 s2);  // Characters to delete from s1  int minDeletions = m - length;  // Characters to insert into s1  int minInsertions = n - length;  // Total operations needed  return minDeletions + minInsertions;  }  static void Main(string[] args) {    string s1 = 'AGGTAB';  string s2 = 'GXTXAYB';  int res = minOperations(s1 s2);  Console.WriteLine(res);  } } 
JavaScript
// JavaScript program to find the minimum of insertion and // deletion using space optimized. function lcs(s1 s2) {  const m = s1.length;  const n = s2.length;  // Initializing a matrix of size (2)*(n+1)  const dp  = Array(2).fill().map(() => Array(n + 1).fill(0));  for (let i = 0; i <= m; i++) {    // Compute current binary index. If i is even  // then curr = 0 else 1  const curr = i % 2;  for (let j = 0; j <= n; j++) {    // Initialize first row and first column with 0  if (i === 0 || j === 0)  dp[curr][j] = 0;  // If the last characters of both substrings  // match  else if (s1[i - 1] === s2[j - 1])  dp[curr][j] = dp[1 - curr][j - 1] + 1;  // If the last characters do not match  // find the maximum LCS length by:  // 1. Excluding the last character of s1  // 2. Excluding the last character of s2  else  dp[curr][j] = Math.max(dp[1 - curr][j]  dp[curr][j - 1]);  }  }  // dp[m & 1][n] contains length of LCS for s1[0..m-1]  // and s2[0..n-1]  return dp[m % 2][n]; } function minOperations(s1 s2) {  const m = s1.length;  const n = s2.length;  // the length of the LCS for s1[0..m-1] and s2[0..n-1]  const length = lcs(s1 s2);  // Characters to delete from s1  const minDeletions = m - length;  // Characters to insert into s1  const minInsertions = n - length;  // Total operations needed  return minDeletions + minInsertions; } const s1 = 'AGGTAB'; const s2 = 'GXTXAYB'; const res = minOperations(s1 s2); console.log(res); 

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