题目描述
找出给出的字符串S中最长的回文子串。假设S的最大长度为1000,并且只存在唯一解。
Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.
示例1
输出
复制"abcba"
动态规划
class Solution {
public:
/**
*
* @param s string字符串
* @return string字符串
*/
string longestPalindrome(string str) {
// write code here
int n=str.length();
if (n==0) return "";
bool dp[n][n];
fill_n(&dp[0][0],n*n,false);
int left=0,right=0,maxLen=0;
for (int j=0;j<n;j++)
{
dp[j][j]=true;
for (int i=0;i<j;i++)
{
dp[i][j]=(str[i]==str[j] && (j-i<2 || dp[i+1][j-1]));
if (dp[i][j]&& (j-i+1>maxLen))
{
left=i;
right=j;
maxLen=j-i+1;
}
}
}
return str.substr(left,right-left+1);
}
};