Created LCS

Algorithms/LongestCommonSubsequence.java

@@ -0,0 +1,70 @@
+import java.util.Scanner;
+
+
+/* Longest Common Subsequence problem implementation using Dynamic Programming */
+
+public class LongestCommonSubsequence 
+{ 
+
+  /* Calculates and returns the LCS for X[0..m-1], Y[0..n-1] */
+  int lcs( char[] X, char[] Y, int m, int n ) 
+  { 
+    int L[][] = new int[m+1][n+1]; 
+
+    for (int i=0; i<=m; i++) 
+    { 
+      for (int 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]); 
+      } 
+    } 
+
+  return L[m][n]; 
+  } 
+
+  // to calculate the maximum of two integers
+  int max(int a, int b) 
+  { 
+    return (a > b)? a : b; 
+  } 
+
+  public static void main(String[] args) 
+  { 
+    LongestCommonSubsequence lcs = new LongestCommonSubsequence(); 
+
+    Scanner obj = new Scanner(System.in);
+    System.out.println("Enter string X : ");
+    String s1 = obj.nextLine(); 
+    System.out.println("Enter string Y : ");
+    String s2 = obj.nextLine();
+
+    char[] X=s1.toCharArray(); 
+    char[] Y=s2.toCharArray(); 
+    int m = X.length; 
+    int n = Y.length; 
+
+    System.out.println("Length of LCS is" + " " + lcs.lcs( X, Y, m, n ) ); 
+  } 
+
+} 
+
+
+/* 
+
+Sample Input :
+
+Enter X : AGGTAB
+Enter Y : GXTXAYB
+
+Sample Output :
+
+Length of LCS is 4
+
+Time Complexity : O(N * M), where N and M are the lengths of two given Strings X and Y.
+
+*/