noip模拟赛 天天和不可描述

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

char s[500010];
int tot, pipei[500010], nextt[500010], x, dir;

int main()
{
    scanf("%s", s + 1);
    int sizee = strlen(s + 1);
    for (int i = 1; i <= sizee; i++)
    {
        if (s[i] == ‘(‘)
            pipei[++tot] = i;
        else
            if (s[i] == ‘)‘)
            {
            nextt[i] = pipei[tot];
            nextt[pipei[tot--]] = i;
            }
    }
    dir = 1, x = 1;
    while (x >= 1 && x <= sizee)
    {
        if (nextt[x])
        {
            x = nextt[x];
            dir = -dir;
        }
        else
            printf("%c", s[x]);
        x += dir;
    }

    return 0;
}