E30086:dance

greedy, http://cs101.openjudge.cn/practice/30086

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int main(){
    int n,d;
    cin>>n>>d;
    vector<int> a(2*n,0);
    for(int i=0;i<2*n;i++){
        cin>>a[i];
    }
    sort(a.begin(),a.end());
    for(int i=0;i<2*n;i+=2){
        if(a[i+1]-a[i]>d){cout<<"No"<<'\n';return 0;}
    }
    cout<<"Yes"<<'\n';
    return 0;
}