最长对称子串 （最长回文字串） pta 7-12

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include<cmath>
#include<vector>
using namespace std;
typedef long long ll;

string a;
int m = 0;
int solve1(int l, int r)
{
    while (l >= 0 && r < a.size() && a[l] == a[r])
    {
        l--;r++;
    }
    return r - 1 - (l + 1) + 1;
}
int solve2(int l, int r)
{
    while (l >= 0 && r < a.size() && a[l] == a[r])
    {
        l--;r++;
    }
    return r - 1 - (l + 1) + 1;
}
int main()
{
    getline(cin, a);
    for (int i = 0; i < a.size(); i++)
    {
        m = max(solve1(i,i), m);
        m = max(solve2(i,i + 1), m);
    }
    cout << m << endl;
}