Merge pull request #44 from nhimanshujain/main

Longest Repeating Subsequence and  Longest Common Prefix

Longest Common Prefix.java

@@ -0,0 +1,25 @@
+public String longestCommonPrefix(String[] strs) {
+    if (strs == null || strs.length == 0) return "";    
+        return longestCommonPrefix(strs, 0 , strs.length - 1);
+}
+
+private String longestCommonPrefix(String[] strs, int l, int r) {
+    if (l == r) {
+        return strs[l];
+    }
+    else {
+        int mid = (l + r)/2;
+        String lcpLeft =   longestCommonPrefix(strs, l , mid);
+        String lcpRight =  longestCommonPrefix(strs, mid + 1,r);
+        return commonPrefix(lcpLeft, lcpRight);
+   }
+}
+
+String commonPrefix(String left,String right) {
+    int min = Math.min(left.length(), right.length());       
+    for (int i = 0; i < min; i++) {
+        if ( left.charAt(i) != right.charAt(i) )
+            return left.substring(0, i);
+    }
+    return left.substring(0, min);
+}

Longest Repeating Subsequence.py

@@ -0,0 +1,31 @@
+class Solution:
+
+    def longestCommonSubsequence(self, text1, text2):
+
+        dp = [[0] * (len(text1)+1) for i in range(len(text2)+1)]        
+
+        for i in range(1,len(text2)+1):
+            for j in range(1,len(text1)+1):
+
+                if text2[i-1] == text1[j-1] and i != j:
+                    dp[i][j] = dp[i-1][j-1] + 1
+
+                else:
+                    dp[i][j] = max(dp[i-1][j], dp[i][j-1])
+
+        # print(dp)
+        return dp[len(text2)][len(text1)]
+
+
+    def LongestRepeatingSubsequence(self, str):
+        # Code here
+        return self.longestCommonSubsequence(str, str)
+
+
+if __name__ == '__main__':
+    T=int(input())
+    for i in range(T):
+        str = input()
+        ob = Solution()
+        ans = ob.LongestRepeatingSubsequence(str)
+        print(ans)