Find the longest palindromic substring in S, running time(about 650ms) exceeds on one test case, need to be improved.
Find the longest palindromic substring in S, running time(about 650ms) exceeds on one test case, need to be improved.

leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation,leonard-sxy/practice-and-accumulation