647

647. Palindromic Substrings

Medium

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Given a string, your task is to count how many palindromic substrings in this string.

The substrings with different start indexes or end indexes are counted as different substrings even they consist of same characters.

Example 1:

Input: "abc" Output: 3 Explanation: Three palindromic strings: "a", "b", "c".

 

Example 2:

Input: "aaa" Output: 6 Explanation: Six palindromic strings: "a", "a", "a", "aa", "aa", "aaa".

 

Note:

1. The input string length won't exceed 1000.

좋은 문제 1개 일때 2개일때 3개 이상일때를 따진다

 

마지막이 좋은 식

 

j = i+k -1 는 index 때문에 1을 뺏다.