Merge pull request #571 from balasbk/master

longest comman subsequences

Author: probot-auto-merge[bot]

C++/LONGEST COMMON SUBSEQUENCE.cpp

@@ -0,0 +1,48 @@
+#include <bits/stdc++.h> 
+  
+int max(int a, int b); 
+  
+/* Returns length of LCS for X[0..m-1], Y[0..n-1] */
+int lcs(char* X, char* Y, int m, int n) 
+{ 
+    int L[m + 1][n + 1]; 
+    int i, j; 
+  
+    /* Following steps build L[m+1][n+1] in bottom up fashion. Note  
+      that L[i][j] contains length of LCS of X[0..i-1] and Y[0..j-1] */
+    for (i = 0; i <= m; i++) { 
+        for (j = 0; j <= n; j++) { 
+            if (i == 0 || j == 0) 
+                L[i][j] = 0; 
+  
+            else if (X[i - 1] == Y[j - 1]) 
+                L[i][j] = L[i - 1][j - 1] + 1; 
+  
+            else
+                L[i][j] = max(L[i - 1][j], L[i][j - 1]); 
+        } 
+    } 
+  
+    /* L[m][n] contains length of LCS for X[0..n-1] and Y[0..m-1] */
+    return L[m][n]; 
+} 
+  
+/* Utility function to get max of 2 integers */
+int max(int a, int b) 
+{ 
+    return (a > b) ? a : b; 
+} 
+  
+/* Driver program to test above function */
+int main() 
+{ 
+    char X[] = "AGGTAB"; 
+    char Y[] = "GXTXAYB"; 
+  
+    int m = strlen(X); 
+    int n = strlen(Y); 
+  
+    printf("Length of LCS is %d\n", lcs(X, Y, m, n)); 
+  
+    return 0; 
+}