1386: 程序员PIPI

优先队列默认是大根堆

#include <bits/stdc++.h>
using namespace std;
vector <pair<int ,int>> vec;

bool cmp(pair<int,int> a, pair<int,int>b){
	return a.first<b.first;
}
int main(){
	int n;
	priority_queue<int, vector<int>, greater<int>> que;;
	while(scanf("%d",&n)!=EOF){
		vec.clear();
		que = priority_queue<int, vector<int>, greater<int>>();
		for(int i=0;i<n;i++){
			int l,r;
			scanf("%d%d",&l,&r);
			vec.push_back({l,r});
		}
		sort(vec.begin(),vec.end(),cmp);
		que.push(vec[0].second);
		for(int i=1;i<n;i++){
			if(vec[i].first<que.top()){
				que.push(vec[i].second);
			}
			else{
				que.pop();
				que.push(vec[i].second);
			}
		}
		printf("%d\n",que.size());
	}
}