Add solution for Longest Common Subsequence and problem.md

Cpp/Longest Common Subsequence/problem.md

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+Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.
+
+A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.
+
+For example, "ace" is a subsequence of "abcde".
+A common subsequence of two strings is a subsequence that is common to both strings.
+
+
+
+Example 1:
+
+Input: text1 = "abcde", text2 = "ace" 
+Output: 3  
+Explanation: The longest common subsequence is "ace" and its length is 3.
+Example 2:
+
+Input: text1 = "abc", text2 = "abc"
+Output: 3
+Explanation: The longest common subsequence is "abc" and its length is 3.
+Example 3:
+
+Input: text1 = "abc", text2 = "def"
+Output: 0
+Explanation: There is no such common subsequence, so the result is 0.
+
+
+Constraints:
+
+1 <= text1.length, text2.length <= 1000
+text1 and text2 consist of only lowercase English characters.

Cpp/Longest Common Subsequence/solution.cpp

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+#include <iostream>
+#include <string>
+using namespace std;
+
+class Solution {
+public:
+    int longestCommonSubsequence(string text1, string text2) {
+       int m = text1.length();
+       int n = text2.length();
+
+        // Creating table
+        int c[m+1][n+1];
+        for(int i = 0; i <= m; i++) {
+            for(int j = 0; j <= n; j++) {
+                c[i][j] = 0;
+            }
+        }
+
+        for(int i = 1; i <= m; i++) {
+            for(int j = 1; j <= n; j++) {
+                if (text1[i-1] == text2[j-1]) {
+                    c[i][j] = c[i-1][j-1] + 1;
+                }
+                else if (c[i-1][j] >= c[i][j-1]) {
+                    c[i][j] = c[i-1][j];
+                }
+                else {
+                    c[i][j] = c[i][j-1];
+                }
+            }
+        }
+
+        return c[m][n];
+    }
+};
+
+int main() {
+    Solution solution;
+
+    // Test Case 1
+    string text1 = "abcde";
+    string text2 = "ace";
+    cout << "Test Case 1 Output: " << solution.longestCommonSubsequence(text1, text2) << endl;
+
+    // Test Case 2
+    text1 = "abc";
+    text2 = "abc";
+    cout << "Test Case 2 Output: " << solution.longestCommonSubsequence(text1, text2) << endl;
+
+    // Test Case 3
+    text1 = "abc";
+    text2 = "def";
+    cout << "Test Case 3 Output: " << solution.longestCommonSubsequence(text1, text2) << endl;
+
+    return 0;
+}