Merge pull request #7465 from SAY-droid427/superseq-java

Added code for shortest supersequence in Java

Java/README.md

@@ -281,6 +281,7 @@ _add list here_
 - [Unique BST](dp/Unique_BST.java)
 - [Job Sequencing to Maximize Profit](dp/JobSequencingToMaximizeProfit.java)
 - [Matrix Chain Multiplication to find the minimum cost](dp/MatrixChainMultiplication.java)
+- [Shortest common supersequence](dp/shortestSupersequence.java)
 - [Perfect Sum Problem](dp/PerfectSumProblem.java)
 - [Floyd Warshall Algorithm](dp/FloydWarshallAlgorithm.java)
 - [Subset Sum to Target](dp/SubsetSumToTarget.java)

Java/dp/shortestSupersequence.java

@@ -0,0 +1,68 @@
+/*
+Given two strings find out the length of the shortest supersequence formed from the two strings.
+ALGORITHM:
+*The idea is to find out the longest common subsequence first.
+*This subsequence will be present once in both the strings.
+*So on adding the length of the two strings the subsequence will be counted twice.
+*Subtract the length of lcs from both the strings and add once.
+*This gives length of shortest supersequence
+*/ 
+
+import java.util.Scanner;
+import java.lang.Math;
+
+public class shortestSuperSeq
+{
+    public static int shortestSuperSequence(String x,String y, int n,int m)
+    {
+        int dp[][]=new int[n+1][m+1];
+
+        for(int i=0;i<n+1;i++)
+        {
+            for(int j=0;j<m+1;j++)
+            {
+                if(i==0 || j==0)
+                dp[i][j]=0;
+            }
+        }
+
+        for(int i=1;i<n+1;i++)
+        {
+            for(int j=1;j<m+1;j++)
+            {
+                if(x.charAt(i-1)==y.charAt(j-1))
+                dp[i][j]=1+dp[i-1][j-1];
+                else
+                dp[i][j]=Math.max(dp[i-1][j],dp[i][j-1]);
+            }
+        }
+        return dp[n][m];
+    }
+
+    public static void main(String args[])
+    {
+        Scanner s=new Scanner(System.in);
+        System.out.println("Enter two strings: ");
+        String x=s.next();
+        String y=s.next();
+        int n=x.length();
+        int m=y.length();
+        System.out.println("The length of the shortest supersequence: "+(n+m-shortestSuperSequence(x,y,n,m)));
+    }
+}
+
+/*
+Time Complexity: O(n*m)
+
+Space complexity: O(n*m)
+
+Input:
+
+Enter two strings: 
+abc
+acd
+
+Output:
+
+The length of the supersequence: 4
+*/