最长对称子串

#include <bits/stdc++.h>
using namespace std;
string str;
int ans;
int len;
int judge(int fore,int back,int slen){
    while(fore >= 0 && back < len){
        if(str[fore] == str[back])
            slen += 2,fore--,back++;
        else break;
    }
    ans = max(ans,slen);
    return ans;
}
int main(){
    //freopen("in","r",stdin);
    ios::sync_with_stdio(0);
    getline(cin,str);
    len = str.size();
    for(int i = 0; i < len; i++){
        //长度为奇数
        judge(i - 1, i + 1,1);
        //长度为偶数
        judge(i,i + 1,0);
    }
    cout << ans;
    return 0;
}