LeetCode: 214. Shortest Palindrome

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LeetCode: 214. Shortest Palindrome

题目描述

Given a string s, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation.

Example 1:

Input: "aacecaaa"
Output: "aaacecaaa"

Example 2:

Input: "abcd"
Output: "dcbabcd"

解题思路

暴力求解: 寻找最长回文前缀。

AC 代码

class Solution {
public:
    string shortestPalindrome(string s) {
        string reverseS(s.rbegin(), s.rend());
        
        for(int i = 0; i < s.size(); ++i)
        {
            if(s.substr(0, s.size()-i) == reverseS.substr(i, s.size()))
            {
                return reverseS.substr(0, i) + s;
            }
        }
        
        return s;
    }
};