Acwing908 区间分组

贪心

#include <bits/stdc++.h>
using namespace std;
#define N 100010
int n;

struct Range{
    int l,r;
    bool operator<(Range& w){
        return l<w.l;
    }
}range[N];

int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>range[i].l>>range[i].r;
    }
    sort(range+1,range+n+1);
    priority_queue<int,vector<int>,greater<int>> q;
    for(int i=1;i<=n;i++){
        auto w = range[i];
        if(q.empty() || q.top()>=w.l) q.push(w.r);
        else{
            q.pop();
            q.push(w.r);
        }
    }
    cout<<q.size()<<endl;

    return 0;
}