added Longest Palindromic Substring

5.LongestPalindromicSubstring.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    string longestPalindrome(string s) {
+        string ans="";
+        int st=0,end=0,len=0;
+        for(int i=0;i<s.size();i++){
+            int l=i,h=i;
+            while(l>=0 && h<s.size() && s[l]==s[h]){
+                if(h-l+1>len){
+                    len=h-l+1;
+                    st=l,end=h;
+                }
+                l--,h++;
+            }
+            l=i,h=i+1;
+             while(l>=0 && h<s.size() && s[l]==s[h]){
+                if(h-l+1>len){
+                    len=h-l+1;
+                    st=l,end=h;
+                }
+                 h++,l--;
+            }
+        }
+        for(int i=st;i<=end;i++){
+            ans+=s[i];
+        }
+        return ans;
+    }
+};

README.md

@@ -166,6 +166,7 @@ Once done kindly update the README.md file by updating the Problems : by adding
 <li>1832. Check if the Sentence Is Pangram. [Easy]</li>
 <li>2007. Find Original Array From Doubled Array. [Medium]</li>
 <li>2095. Delete the Middle Node of a Linked List. [Medium]</li>
+<li>5. Longest Palindromic Substring [Medium].</li>
 </ul>
 <br>
 <hr>