Yuhao and a Parenthesis

https://codeforces.com/problemset/problem/1097/C

C++版本一

题解：首先保证每个字符串只多(和)其中一个，然后匹配就好了

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=1000000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,q,ans;
int a[N];
char str[N];
stack<char>st;
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    scanf("%d",&n);
    memset(a,0,sizeof(a));
    for(int i=1;i<=n;i++){
        cin>>str;
        while (!st.empty()) st.pop();
        st.push(str[0]);
        for (int j=1;str[j]!='\0';++j)
        {
            if (!st.empty())
            {
                if (st.top()=='('&&str[j]==')')
                {
                    st.pop();
                }
                else st.push(str[j]);
            }
            else st.push(str[j]);
        }
        int ls=0,rs=0;
        while (!st.empty())
        {
            char xx=st.top();
            st.pop();
            if (xx=='(') ls++;
            else rs++;
        }
        if (ls!=0&&rs!=0)
        {
            continue;
        }
        else if (ls==0&&rs==0)
        {
            a[500000]++;
        }
        else if (rs!=0)
        {
            a[500000-rs]++;
        }else a[500000+ls]++;

    }
    for(int i=1;i<=500000;i++){
       ans+=min(a[500000-i],a[500000+i]);
    }
    ans+=a[500000]/2;
    cout << ans << endl;
    //cout << "Hello world!" << endl;
    return 0;
}

C++版本二

#include<stdio.h>
#include<string.h>
#include<stack>
using namespace std;
const int mx=5e5+10;
char str[mx];
int num=0;
int sum[mx];
int sum2[mx];
int n;
int ans=0;
stack<char>st;
int main()
{
    int t;
    scanf("%d",&t);
    for (int i=1;i<=t;++i)
    {
        scanf("%s",str);
        while (!st.empty()) st.pop();
        st.push(str[0]);
        for (int j=1;str[j]!='\0';++j)
        {
            if (!st.empty())
            {
                if (st.top()=='('&&str[j]==')')
                {
                    st.pop();
                }
                else st.push(str[j]);
            }
            else st.push(str[j]);
        }
        int ls=0,rs=0;
        while (!st.empty())
        {
            char xx=st.top();
            st.pop();
            if (xx=='(') ls++;
            else rs++;
        }
        if (ls!=0&&rs!=0)
        {
            continue;
        }
        else if (ls==0&&rs==0)
        {
            num++;
        }
        else if (rs!=0)
        {
            sum2[rs]++;
        }
        else sum[ls]++;
    }
    for (int i=1;i<=mx-10;++i)
    {
        if (sum[i]>sum2[i])
        {
            ans+=sum2[i];
        }
        else ans+=sum[i];
    }
    ans+=num/2;
    printf("%d\n",ans);
}