Create yeongu.cpp

Author: YeonguChoe

palindromic-substrings/yeongu.cpp

@@ -0,0 +1,42 @@
+// TC: O(n^2) For문 안에서 while문 사용하는 함수 호출
+// SC: O(1)
+
+class Solution {
+public:
+    int find_palindrome1(string& original_text, int index) {
+        int cnt = 0;
+        int left_ptr = index, right_ptr = index;
+
+        while (left_ptr >= 0 and right_ptr < original_text.size() and
+               original_text[left_ptr] == original_text[right_ptr]) {
+            cnt += 1;
+            left_ptr -= 1;
+            right_ptr += 1;
+        }
+        return cnt;
+    }
+
+    int find_palindrome2(string& original_text, int index) {
+        int cnt = 0;
+        int left_ptr = index, right_ptr = index + 1;
+
+        while (left_ptr >= 0 and right_ptr < original_text.size() and
+               original_text[left_ptr] == original_text[right_ptr]) {
+            cnt++;
+            left_ptr--;
+            right_ptr++;
+        }
+        return cnt;
+    }
+
+    int countSubstrings(string& s) {
+        int output = 0;
+        for (int i = 0; i < s.size(); i++) {
+            output += find_palindrome1(s, i);
+        }
+        for (int i = 0; i < s.size() - 1; i++) {
+            output += find_palindrome2(s, i);
+        }
+        return output;
+    }
+};