HDU1870

hdu1870.cpp

#include <cstdio>
#include <ctime>
#include <cstdlib>
#include <iostream>
#include <cstring>
#include <vector>
#include <fstream>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <string>
#define MAX(a,b) (a>b?a:b)
#define sd(x) scanf("%d",&x)
#define sdd(a,b) scanf("%d%d",&a,&b)
#define sddd(a,b,c) scanf("%d%d%d",&a,&b,&c)
#define slflf(x,y) scanf("%lf%lf",&x,&y)
#define abs(x) (x<0?(-x):x)
#define MAX(a,b) (a>b?a:b)
#define MIN(a,b) (a<b?a:b)
using namespace std;

char input[1100];
stack<char>beforeB;
stack<char>afterB;

int main()
{
    while(gets(input))
    {
        while(!beforeB.empty()) beforeB.pop();
        while(!afterB.empty()) afterB.pop();
        int len = strlen(input);
        bool hasBAppeared = false;
        int cnt=0;
        for (int i=0;i<len;i++)
        {
            if (!hasBAppeared)
            {
                if (input[i]=='(') beforeB.push('(');
                else if (input[i]==')') beforeB.pop();
                else hasBAppeared=true;
            }
            else
            {
                if (input[i]=='(') afterB.push('(');
                else
                {
                    if (!afterB.empty()) afterB.pop();
                    else {beforeB.pop();cnt++;}
                }
            }
        }
        cout << cnt << endl;
    }
}