括号序列的条件

一个序列是括号序列的条件是：在所有位置，前面（含当前位置）的左括号的数量大于等于右括号的数量，且最终相等。

例题：

https://codeforces.com/contest/1709/problem/C

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;


void YD()
{
    string str;
    cin >> str;
    int l = 0, r = 0, q = 0;
    for (auto ch : str)
    {
        if (ch == '(') l++;
        else if (ch == ')') r++;
        else q++;
    }
    int x = r + q - l;
    x >>= 1;
    if (x < 0)
    {
        cout << "YES" << endl;
        return;
    }

    int n = str.size();
    vector<int> mark(n);
    for (int i = 0; i < n; i++)
    {
        if (str[i] == '?')
        {
            if (x)
                mark[i] = 1, x--;
            else
                mark[i] = 2;
        }
    }
    int ll = -1, rr = -1;
    for (int i = 0; i < n; i++)
    {
        if (mark[i] == 2)
        {
            rr = i; break;
        }
    }
    for (int i = n-1; i >=0; i--)
    {
        if (mark[i] == 1)
        {
            ll = i; break;
        }
    }
    if (ll == -1 || rr == -1)
    {
        cout << "YES" << endl;
        return;
    }
    mark[ll] = 2;
    mark[rr] = 1;
    for (int i = 0; i < n; i++)
    {
        if (mark[i] == 1)
            str[i] = '(';
        if (mark[i] == 2)
            str[i] = ')';
    }
    ll = 0, rr = 0;
    for (int i = 0; i < n; i++)
    {
        if (str[i] == '(')
            ll++;
        else
            rr++;
        if (rr > ll)
        {
            cout << "YES" << endl;
            return;
        }
    }
    cout << "NO" << endl;

}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int T = 1;
    cin >> T;
    while (T--)
    {
        YD();
    }
    return 0;
}