Codeforces Round #808 (Div. 2）

A

思路：a【1】是其他元素的因子，不易证

/**/
#include <bits/stdc++.h>
#define rep(i, a, b) for(int i = a; i <= b; i ++)
#define endl '\n'
using namespace std;
const int N = 100 + 5, INF = 1e9 +5;

int a[N];

void s(){
  int n ;cin >> n;
  
  for(int i = 1; i <= n; i ++) cin >> a[i];
  

  for(int i = 2; i <= n ;i ++){
    if(a[i] % a[1] != 0) {
      cout << "NO\n"; return ;
    }
  }
  
  cout << "YES\n";
}

int main(){

  cin.tie(0);cout.tie(0);ios::sync_with_stdio(0);


  int t; cin >>t; while(t--) s();
  
  
  return 0;
}

B

思路：检查l--r之间是否有i的倍数

#include<iostream>
#include<cstring>
using namespace std;
typedef long long LL;
const int maxn = 1e5 + 5, INF = 0x3f3f3f3f;
int ans[maxn];

int main(){

    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);

    int T;
    cin >> T;
    while(T--){
        int n, l, r;
        cin >> n >> l >> r;
        bool success = 1;
        for(int i = 1; i <= n; i++){
            int t = (l + i - 1) / i * i;
            if (t > r){
                success = 0;
                break;
            }
            ans[i] = t;
        }
        if (success){
            cout << "YES" << '\n';
            for(int i = 1; i <= n; i++) cout << ans[i] << " \n"[i == n];
        }
        else cout << "NO" << '\n';
    }

}

C