http://whu.contest.codeforces.com/group/LqmZzHyOQN/contest/234192/problem/D

題解：

其實全部打亂重新排就行了

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=1000000+100;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,q;
char str[N];
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        scanf("%s",str);
        int a[10]={6,2,5,5,4,5,6,3,7,6};
        int sum=0;
        for(int i=0;i<n;i++){
            sum+=a[str[i]-'0'];
        }
        int b[10]={0,0,1,7,4,5,9,8};
        string ans="";
        for(int i=0;i<n;i++){
            if(i==n-1){
                ans+='0'+b[sum];
                break;
            }
            if((n-i-1)*2<=sum-6){
                sum-=6;
                ans+="9";
            }

            else if((n-i-1)*2<=sum-3){
                sum-=3;
                ans+="7";
            }

            else if((n-i-1)*2<=sum-2){
                sum-=2;
                ans+="1";
            }

        }
        cout << ans << endl;
    }

    //cout << "Hello world!" << endl;
    return 0;
}