字符串运用-密码截取(HJ85)

#include <iostream>
#include <vector>
#include <string>

using namespace std;


int longestPalindrome(string& s) 
{
    if (s.size() == 0) return 0;
    int start = 0;
    int maxLen = 0;
    int n = s.size();

    vector<vector<bool>> d(n,vector<bool>(n,false));

    for (int i = n - 1; i >= 0; i--)
    {
        for (int j = i; j < n; j++)
        {
            if (i == j) d[i][j] = true;
            else if (i + 1 == j) d[i][j] = s[i] == s[j];
            else d[i][j] = ( s[i] == s[j] && d[i+1][j-1]);

            if (d[i][j] && (j - i + 1) > maxLen)
            {
                start = i;
                maxLen = j - i + 1;
            }
        }
    }

    return maxLen;
}

int main()
{
    string s = "";

    while (cin >> s)
    {
        cout << longestPalindrome(s) << endl;
    }

    return 0;
}