3.1circle

Posted 2021-01-25 wzl19981116

就是括号匹配的题目，如果有交集就是NO

#include<iostream> 
#include<cstring>
#include<stdio.h>
#include<stack>
#include<algorithm> 
using namespace std;
stack<int> s;
int a[200005];
int main()
{
    int t,n,m,temp1,temp2,i;
    scanf("%d",&t);
    while(t--)
    {
        int n,m;
        scanf("%d%d",&n,&m);
        memset(a,0,sizeof (a));
        while(!s.empty()) s.pop();
        for(i=1;i<=m;i++)
        {
            scanf("%d%d",&temp1,&temp2);
            a[temp1]=i;a[temp2]=i;
        }
        for(i=1;i<=2*n;i++)
        {
            if(a[i]==0) continue;
            if(s.empty()) s.push(a[i]);
            else
            {
                if(a[i]==s.top()) s.pop(); 
                else s.push(a[i]);
            }
        }
        if(s.empty()) printf("YES
");
        else printf("NO
");
    }
    
}