60分小清新堆代码，求hack

#include <bits/stdc++.h>
#define ll long long
using namespace std;

struct node {
    ll pos,type,id;
    bool operator<(node b)const {
        return id<b.id;
    }
} nodes[2005];
ll cnter=0,vis[2005],qwq[2005];

int main() {
    ll n,m;
    cin >> n >> m;
    for (ll i=1; i<=m; i++) {
        ll f,t;
        cin >> f >> t;
        nodes[++cnter]= {f,1,i};
        nodes[++cnter]= {t,0,i};
    }
    sort(nodes+1,nodes+cnter+1,[](node a,node b) {
        if (a.type==0&&b.type==0)
        return (a.pos==b.pos?a.id<b.id:a.pos<b.pos);
        else
        return (a.pos==b.pos?a.id>b.id:a.pos<b.pos);
    });
    priority_queue<node> pq;
    for (ll i=1; i<=cnter; i++) {
        if (nodes[i].type==1) {
            pq.push(nodes[i]);
        }
        node tp= {0,0,0};
        if (!pq.empty())
            tp=pq.top();
        while (!pq.empty()&&qwq[tp.id]) {
            pq.pop();
            tp=pq.top();
        }
        if (!qwq[tp.id]&&(abs(tp.pos-nodes[i].pos)>=1||tp.id==nodes[i].id))
            vis[tp.id]=1;
//      cout << tp.id << " "<< nodes[i].pos << endl;
        if (nodes[i].type==0) {
            qwq[nodes[i].id]=1;
        }
    }
    ll cnt=0;
    for (ll i=1; i<=m; i++)if (vis[i])cnt++;
    cout << cnt;
    return 0;
}