题解归档 - cf2220A

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• 本地编号：cf2220A
• 本地来源：problems/cf2220A/idea.md
• 题目链接：https://codeforces.com/contest/2220/problem/A
• 原始标题：cf2220A - Blocked

思路

cf2220A - Blocked

Pattern

All numbers are positive. If two equal values exist, whichever copy appears
later is blocked by the earlier equal copy, so the answer is impossible.

If all values are distinct, sort them in decreasing order. For any position,
all previous values are strictly larger than the current value, and every
non-empty subset sum of previous values is therefore larger than the current
value. Hence no position is blocked.

Algorithm

• If any duplicate exists, print -1.
• Otherwise print the array in descending order.

Checks

• python tools/math_reasoning_search.py --problem cf2220A -n 5 - required
  precheck done.

代码

来源：problems/cf2220A/solution.cpp

/* Author: likely
 * Time: 2026-06-08 00:05:00
**/
#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll s[205],cnt[105];
int main(){
    ll t,n,i,zc;
    cin>>t;
    while(t--){
        cin>>n;
        zc=0;
        for(i=1;i<=100;i++) cnt[i]=0;
        for(i=1;i<=n;i++){
            cin>>s[i];
            if(cnt[s[i]]) zc=1;
            cnt[s[i]]++;
        }
        if(zc){
            cout<<"-1\n";
            continue;
        }
        sort(s+1,s+n+1,greater<ll>());
        for(i=1;i<=n;i++){
            if(i>1) cout<<" ";
            cout<<s[i];
        }
        cout<<"\n";
    }
    return 0;
}