Create recursion

recursion

@@ -0,0 +1,68 @@
+#include <iostream>
+#include <string>
+#include <algorithm>
+using namespace std;
+
+// Expand in both directions of `low` and `high` to find
+// palindrome of length `k`
+bool expand(string str, int low, int high, int k)
+{
+    // run till `str[low.high]` is not a palindrome
+    while (low >= 0 && high < str.length() && (str[low] == str[high]))
+    {
+        // return true palindrome of length `k` is found
+            if (high - low + 1 == k) {
+                return true;
+            }
+
+        // Expand in both directions
+        low--, high++;
+    }
+
+    // return false if palindrome of length `k` is not found
+    return false;
+}
+
+// Function to check if a palindromic substring of length `k` exists or not
+bool longestPalindromicSubstring(string str, int k)
+{
+    for (int i = 0; i < str.length() - 1; i++)
+    {
+        // check if odd or even length palindrome of length `k` exists,
+        // which have `str[i]` as its midpoint
+        if (expand(str, i, i, k) || expand(str, i, i + 1, k)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+// Function to check if a given string is a rotated palindrome or not
+bool isRotatedPalindrome(string str)
+{
+    // length of the given string
+    int n = str.length();
+
+    // return true if the longest palindromic substring of length `n`
+    // exists in the string `str + str`
+    return longestPalindromicSubstring(str + str, n);
+}
+
+int main()
+{
+    // palindromic string
+    string str = "ABCCBA";
+
+    // rotate it by 2 units
+    rotate(str.begin(), str.begin() + 2, str.end());
+
+    if (isRotatedPalindrome(str)) {
+        cout << "The string is a rotated palindrome";
+    }
+    else {
+        cout << "The string is not a rotated palindrome";
+    }
+
+    return 0;
+}