logo

Imprimer toutes les sous-séquences communes les plus longues dans l'ordre lexicographique

Essayez-le sur GfG Practice ' title= #practiceLinkDiv { display : aucun !important; }

Vous disposez de deux chaînes dont la tâche est d'imprimer toutes les sous-séquences communes les plus longues dans l'ordre lexicographique.

Exemples : 

Input : str1 = 'abcabcaa' str2 = 'acbacba' Output: ababa abaca abcba acaba acaca acbaa acbca
Recommended Practice Imprimer toutes les séquences LCS Essayez-le !

Ce problème est une extension de sous-séquence commune la plus longue . Nous trouvons d'abord la longueur du LCS et stockons tous les LCS dans une table 2D à l'aide de la mémorisation (ou programmation dynamique). Ensuite, nous recherchons tous les caractères de « a » à « z » (pour afficher l’ordre de tri) dans les deux chaînes. Si un caractère est trouvé dans les deux chaînes et que les positions actuelles du caractère mènent au LCS, nous recherchons de manière récursive toutes les occurrences avec la longueur LCS actuelle plus 1. 



Vous trouverez ci-dessous la mise en œuvre de l'algorithme. 

C++
// C++ program to find all LCS of two strings in // sorted order. #include   #define MAX 100 using namespace std; // length of lcs int lcslen = 0; // dp matrix to store result of sub calls for lcs int dp[MAX][MAX]; // A memoization based function that returns LCS of // str1[i..len1-1] and str2[j..len2-1] int lcs(string str1 string str2 int len1 int len2  int i int j) {  int &ret = dp[i][j];  // base condition  if (i==len1 || j==len2)  return ret = 0;  // if lcs has been computed  if (ret != -1)  return ret;  ret = 0;  // if characters are same return previous + 1 else  // max of two sequences after removing i'th and j'th  // char one by one  if (str1[i] == str2[j])  ret = 1 + lcs(str1 str2 len1 len2 i+1 j+1);  else  ret = max(lcs(str1 str2 len1 len2 i+1 j)  lcs(str1 str2 len1 len2 i j+1));  return ret; } // Function to print all routes common sub-sequences of // length lcslen void printAll(string str1 string str2 int len1 int len2  char data[] int indx1 int indx2 int currlcs) {  // if currlcs is equal to lcslen then print it  if (currlcs == lcslen)  {  data[currlcs] = '';  puts(data);  return;  }  // if we are done with all the characters of both string  if (indx1==len1 || indx2==len2)  return;  // here we have to print all sub-sequences lexicographically  // that's why we start from 'a'to'z' if this character is  // present in both of them then append it in data[] and same  // remaining part  for (char ch='a'; ch<='z'; ch++)  {  // done is a flag to tell that we have printed all the  // subsequences corresponding to current character  bool done = false;  for (int i=indx1; i<len1; i++)  {  // if character ch is present in str1 then check if  // it is present in str2  if (ch==str1[i])  {  for (int j=indx2; j<len2; j++)  {  // if ch is present in both of them and  // remaining length is equal to remaining  // lcs length then add ch in sub-sequence  if (ch==str2[j] &&  dp[i][j] == lcslen-currlcs)  {  data[currlcs] = ch;  printAll(str1 str2 len1 len2 data i+1 j+1 currlcs+1);  done = true;  break;  }  }  }  // If we found LCS beginning with current character.   if (done)  break;  }  } } // This function prints all LCS of str1 and str2 // in lexicographic order. void prinlAllLCSSorted(string str1 string str2) {  // Find lengths of both strings  int len1 = str1.length() len2 = str2.length();  // Find length of LCS  memset(dp -1 sizeof(dp));  lcslen = lcs(str1 str2 len1 len2 0 0);  // Print all LCS using recursive backtracking  // data[] is used to store individual LCS.  char data[MAX];  printAll(str1 str2 len1 len2 data 0 0 0); } // Driver program to run the case int main() {  string str1 = 'abcabcaa' str2 = 'acbacba';  prinlAllLCSSorted(str1 str2);  return 0; } 
Java
// Java program to find all LCS of two strings in  // sorted order.  import java.io.*; class GFG {  static int MAX = 100;  // length of lcs   static int lcslen = 0;   // dp matrix to store result of sub calls for lcs   static int[][] dp = new int[MAX][MAX];   // A memoization based function that returns LCS of   // str1[i..len1-1] and str2[j..len2-1]   static int lcs(String str1 String str2   int len1 int len2 int i int j)   {   int ret = dp[i][j];   // base condition   if (i == len1 || j == len2)   return ret = 0;   // if lcs has been computed   if (ret != -1)   return ret;   ret = 0;   // if characters are same return previous + 1 else   // max of two sequences after removing i'th and j'th   // char one by one   if (str1.charAt(i) == str2.charAt(j))   ret = 1 + lcs(str1 str2 len1 len2 i + 1 j + 1);   else  ret = Math.max(lcs(str1 str2 len1 len2 i + 1 j)   lcs(str1 str2 len1 len2 i j + 1));   return dp[i][j]=ret;   }   // Function to print all routes common sub-sequences of   // length lcslen   static void printAll(String str1 String str2 int len1 int len2   char[] data int indx1 int indx2 int currlcs)   {   // if currlcs is equal to lcslen then print it   if (currlcs == lcslen)   {   data[currlcs] = '';   System.out.println(new String(data));   return;   }   // if we are done with all the characters of both string   if (indx1 == len1 || indx2 == len2)   return;   // here we have to print all sub-sequences lexicographically   // that's why we start from 'a'to'z' if this character is   // present in both of them then append it in data[] and same   // remaining part   for (char ch ='a'; ch <='z'; ch++)   {   // done is a flag to tell that we have printed all the   // subsequences corresponding to current character   boolean done = false;   for (int i = indx1; i < len1; i++)   {   // if character ch is present in str1 then check if   // it is present in str2   if (ch == str1.charAt(i))   {   for (int j = indx2; j < len2; j++)   {  // if ch is present in both of them and   // remaining length is equal to remaining   // lcs length then add ch in sub-sequence   if (ch == str2.charAt(j) &&   dp[i][j] == lcslen - currlcs)   {   data[currlcs] = ch;   printAll(str1 str2 len1 len2   data i + 1 j + 1 currlcs + 1);   done = true;   break;   }   }   }   // If we found LCS beginning with current character.   if (done)   break;   }   }   }   // This function prints all LCS of str1 and str2   // in lexicographic order.   static void prinlAllLCSSorted(String str1 String str2)   {   // Find lengths of both strings   int len1 = str1.length() len2 = str2.length();   // Find length of LCS   for(int i = 0; i < MAX; i++)  {  for(int j = 0; j < MAX; j++)  {  dp[i][j] = -1;  }  }  lcslen = lcs(str1 str2 len1 len2 0 0);   // Print all LCS using recursive backtracking   // data[] is used to store individual LCS.   char[] data = new char[MAX];   printAll(str1 str2 len1 len2 data 0 0 0);   }   // Driver code  public static void main(String[] args)   {  String str1 = 'abcabcaa' str2 = 'acbacba';   prinlAllLCSSorted(str1 str2);   } } // This code is contributed by divyesh072019 
Python3
# Python3 program to find all LCS of two strings in # sorted order. MAX=100 lcslen = 0 # dp matrix to store result of sub calls for lcs dp=[[-1 for i in range(MAX)] for i in range(MAX)] # A memoization based function that returns LCS of # str1[i..len1-1] and str2[j..len2-1] def lcs(str1 str2 len1 len2 i j): # base condition if (i == len1 or j == len2): dp[i][j] = 0 return dp[i][j] # if lcs has been computed if (dp[i][j] != -1): return dp[i][j] ret = 0 # if characters are same return previous + 1 else # max of two sequences after removing i'th and j'th # char one by one if (str1[i] == str2[j]): ret = 1 + lcs(str1 str2 len1 len2 i + 1 j + 1) else: ret = max(lcs(str1 str2 len1 len2 i + 1 j) lcs(str1 str2 len1 len2 i j + 1)) dp[i][j] = ret return ret # Function to print all routes common sub-sequences of # length lcslen def printAll(str1 str2 len1 len2data indx1 indx2 currlcs): # if currlcs is equal to lcslen then print if (currlcs == lcslen): print(''.join(data[:currlcs])) return # if we are done with all the characters of both string if (indx1 == len1 or indx2 == len2): return # here we have to print all sub-sequences lexicographically # that's why we start from 'a'to'z' if this character is # present in both of them then append it in data[] and same # remaining part for ch in range(ord('a')ord('z') + 1): # done is a flag to tell that we have printed all the # subsequences corresponding to current character done = False for i in range(indx1len1): # if character ch is present in str1 then check if # it is present in str2 if (chr(ch)==str1[i]): for j in range(indx2 len2): # if ch is present in both of them and # remaining length is equal to remaining # lcs length then add ch in sub-sequence if (chr(ch) == str2[j] and dp[i][j] == lcslen-currlcs): data[currlcs] = chr(ch) printAll(str1 str2 len1 len2 data i + 1 j + 1 currlcs + 1) done = True break # If we found LCS beginning with current character. if (done): break # This function prints all LCS of str1 and str2 # in lexicographic order. def prinlAllLCSSorted(str1 str2): global lcslen # Find lengths of both strings len1len2 = len(str1)len(str2) lcslen = lcs(str1 str2 len1 len2 0 0) # Print all LCS using recursive backtracking # data[] is used to store individual LCS. data = ['a' for i in range(MAX)] printAll(str1 str2 len1 len2 data 0 0 0) # Driver program to run the case if __name__ == '__main__': str1 = 'abcabcaa' str2 = 'acbacba' prinlAllLCSSorted(str1 str2) # This code is contributed by mohit kumar 29 
C#
// C# program to find all LCS of two strings in  // sorted order.  using System; class GFG  {   static int MAX = 100;    // length of lcs   static int lcslen = 0;     // dp matrix to store result of sub calls for lcs   static int[] dp = new int[MAXMAX];     // A memoization based function that returns LCS of   // str1[i..len1-1] and str2[j..len2-1]   static int lcs(string str1 string str2   int len1 int len2 int i int j)   {   int ret = dp[i j];     // base condition   if (i == len1 || j == len2)   return ret = 0;     // if lcs has been computed   if (ret != -1)   return ret;     ret = 0;     // if characters are same return previous + 1 else   // max of two sequences after removing i'th and j'th   // char one by one   if (str1[i] == str2[j])   ret = 1 + lcs(str1 str2 len1 len2 i + 1 j + 1);   else  ret = Math.Max(lcs(str1 str2 len1 len2 i + 1 j)   lcs(str1 str2 len1 len2 i j + 1));   return ret;   }     // Function to print all routes common sub-sequences of   // length lcslen   static void printAll(string str1 string str2 int len1 int len2   char[] data int indx1 int indx2 int currlcs)   {   // if currlcs is equal to lcslen then print it   if (currlcs == lcslen)   {   data[currlcs] = '';   Console.WriteLine(new string(data));   return;   }     // if we are done with all the characters of both string   if (indx1 == len1 || indx2 == len2)   return;     // here we have to print all sub-sequences lexicographically   // that's why we start from 'a'to'z' if this character is   // present in both of them then append it in data[] and same   // remaining part   for (char ch='a'; ch<='z'; ch++)   {   // done is a flag to tell that we have printed all the   // subsequences corresponding to current character   bool done = false;     for (int i = indx1; i < len1; i++)   {   // if character ch is present in str1 then check if   // it is present in str2   if (ch == str1[i])   {   for (int j = indx2; j < len2; j++)   {   // if ch is present in both of them and   // remaining length is equal to remaining   // lcs length then add ch in sub-sequence   if (ch == str2[j] &&   lcs(str1 str2 len1 len2 i j) == lcslen-currlcs)   {   data[currlcs] = ch;   printAll(str1 str2 len1 len2 data i+1 j+1 currlcs+1);   done = true;   break;   }   }   }     // If we found LCS beginning with current character.   if (done)   break;   }   }   }     // This function prints all LCS of str1 and str2   // in lexicographic order.   static void prinlAllLCSSorted(string str1 string str2)   {   // Find lengths of both strings   int len1 = str1.Length len2 = str2.Length;     // Find length of LCS   for(int i = 0; i < MAX; i++)  {  for(int j = 0; j < MAX; j++)  {  dp[i j] = -1;  }  }  lcslen = lcs(str1 str2 len1 len2 0 0);     // Print all LCS using recursive backtracking   // data[] is used to store individual LCS.   char[] data = new char[MAX];   printAll(str1 str2 len1 len2 data 0 0 0);   }   // Driver code  static void Main()   {  string str1 = 'abcabcaa' str2 = 'acbacba';   prinlAllLCSSorted(str1 str2);   } } // This code is contributed by divyeshrabadiya07 
JavaScript
<script> // Javascript program to find all LCS of two strings in // sorted order.    let MAX = 100;  // length of lcs  let lcslen = 0;    // dp matrix to store result of sub calls for lcs  let dp = new Array(MAX);    // A memoization based function that returns LCS of  // str1[i..len1-1] and str2[j..len2-1]  function lcs(str1str2len1len2ij)  {  let ret = dp[i][j];    // base condition  if (i == len1 || j == len2)  return ret = 0;    // if lcs has been computed  if (ret != -1)  return ret;   ret = 0;    // if characters are same return previous + 1 else  // max of two sequences after removing i'th and j'th  // char one by one  if (str1[i] == str2[j])  ret = 1 + lcs(str1 str2 len1 len2 i + 1 j + 1);  else  ret = Math.max(lcs(str1 str2 len1 len2 i + 1 j)  lcs(str1 str2 len1 len2 i j + 1));  return ret;  }    // Function to print all routes common sub-sequences of  // length lcslen  function printAll(str1str2len1len2dataindx1indx2currlcs)  {  // if currlcs is equal to lcslen then print it  if (currlcs == lcslen)  {  data[currlcs] = null;  document.write(data.join('')+'  
'
); return; } // if we are done with all the characters of both string if (indx1 == len1 || indx2 == len2) return; // here we have to print all sub-sequences lexicographically // that's why we start from 'a'to'z' if this character is // present in both of them then append it in data[] and same // remaining part for (let ch ='a'.charCodeAt(0); ch <='z'.charCodeAt(0); ch++) { // done is a flag to tell that we have printed all the // subsequences corresponding to current character let done = false; for (let i = indx1; i < len1; i++) { // if character ch is present in str1 then check if // it is present in str2 if (ch == str1[i].charCodeAt(0)) { for (let j = indx2; j < len2; j++) { // if ch is present in both of them and // remaining length is equal to remaining // lcs length then add ch in sub-sequence if (ch == str2[j].charCodeAt(0) && lcs(str1 str2 len1 len2 i j) == lcslen - currlcs) { data[currlcs] = String.fromCharCode(ch); printAll(str1 str2 len1 len2 data i + 1 j + 1 currlcs + 1); done = true; break; } } } // If we found LCS beginning with current character. if (done) break; } } } // This function prints all LCS of str1 and str2 // in lexicographic order. function prinlAllLCSSorted(str1str2) { // Find lengths of both strings let len1 = str1.length len2 = str2.length; // Find length of LCS for(let i = 0; i < MAX; i++) { dp[i]=new Array(MAX); for(let j = 0; j < MAX; j++) { dp[i][j] = -1; } } lcslen = lcs(str1 str2 len1 len2 0 0); // Print all LCS using recursive backtracking // data[] is used to store individual LCS. let data = new Array(MAX); printAll(str1 str2 len1 len2 data 0 0 0); } // Driver code let str1 = 'abcabcaa' str2 = 'acbacba'; prinlAllLCSSorted(str1 str2); // This code is contributed by unknown2108 </script>

Sortir
ababa abaca abcba acaba acaca acbaa acbca

Complexité temporelle : O(m*n*p) où 'm' est la longueur du tableau de caractères, 'n' est la longueur du tableau1 et 'p' est la longueur du tableau2.
Complexité spatiale : O(m*n) parce que nous utilisons une matrice 2D de taille m*n pour stocker le résultat.