Ped-Air TASK_148

#include<iostream>
#include<stack>
#include<algorithm>
using namespace std;
typedef long long ll;

typedef struct{
    int id;
    ll time;
    bool isin;
}task;

bool mycmp(task a,task b){
    return a.time < b.time;
}

int main()
{
    int n;
    cin>>n;
    stack<int> stack;
    task arr[2*n];

    for(int i=0;i<2*n;i++){
        ll t;
        cin>>t;
        arr[i] = {i/2,t,(i+1)%2};
    }
    sort(arr,arr+2*n,mycmp);
    for(int i=0;i<2*n;i++){
        if(arr[i].isin){
            stack.push(arr[i].id);
        }else{
            if(stack.top() != arr[i].id){
                printf("No");
                return 0;
            }else{
                stack.pop();
            }
        }
    }
    printf("Yes");
    return 0;
}