Codeforces Round #602 (Div. 2, based on Technocup 2020 Elimination Round 3) B. Box 贪心

Posted 2020-11-22 qscqesze

B. Box

Permutation p is a sequence of integers p=[p1,p2,…,pn], consisting of n distinct (unique) positive integers between 1 and n, inclusive. For example, the following sequences are permutations: [3,4,1,2], [1], [1,2]. The following sequences are not permutations: [0], [1,2,1], [2,3], [0,1,2].

The important key is in the locked box that you need to open. To open the box you need to enter secret code. Secret code is a permutation p of length n.

You don‘t know this permutation, you only know the array q of prefix maximums of this permutation. Formally:

q1=p1,
q2=max(p1,p2),
q3=max(p1,p2,p3),
...
qn=max(p1,p2,…,pn).
You want to construct any possible suitable permutation (i.e. any such permutation, that calculated q for this permutation is equal to the given array).

Input

The first line contains integer number t (1≤t≤104) — the number of test cases in the input. Then t test cases follow.

The first line of a test case contains one integer n (1≤n≤105) — the number of elements in the secret code permutation p.

The second line of a test case contains n integers q1,q2,…,qn (1≤qi≤n) — elements of the array q for secret permutation. It is guaranteed that qi≤qi+1 for all i (1≤i<n).

The sum of all values n over all the test cases in the input doesn‘t exceed 105.

Output

For each test case, print:

If it‘s impossible to find such a permutation p, print "-1" (without quotes).
Otherwise, print n distinct integers p1,p2,…,pn (1≤pi≤n). If there are multiple possible answers, you can print any of them.

Example

input
4
5
1 3 4 5 5
4
1 1 3 4
2
2 2
1
1
output
1 3 4 5 2
-1
2 1
1

Note

In the first test case of the example answer [1,3,4,5,2] is the only possible answer:

q1=p1=1;
q2=max(p1,p2)=3;
q3=max(p1,p2,p3)=4;
q4=max(p1,p2,p3,p4)=5;
q5=max(p1,p2,p3,p4,p5)=5.
It can be proved that there are no answers for the second test case of the example.

题意

现在给你前缀最大值是多少，让你还原这个排列，问你是否有解。

题解

给了你前缀最大值，我们现在如果发现前缀最大值变化了，那么这个位置肯定是这个最大值，否则就插入了一个小的数，那么我们插入最小的就好。

代码

#include<bits/stdc++.h>
using namespace std;

vector<int>Q;
void solve(){
    int n;scanf("%d",&n);
    Q.clear();
    vector<int> ans;
    set<int>S;
    for(int i=0;i<n;i++){
        int x;scanf("%d",&x);
        Q.push_back(x);
        S.insert(i+1);
    }
    int mx = 0;
    for(int i=0;i<n;i++){
        if(Q[i]>mx){
            if(S.count(Q[i])){
                S.erase(Q[i]);
                ans.push_back(Q[i]);
            }else{
                cout<<"-1"<<endl;
                return;
            }
            mx = Q[i];
        }else{
            if(*S.begin()>mx){
                cout<<"-1"<<endl;
                return;
            }else{
                ans.push_back(*S.begin());
                S.erase(S.begin());
            }
        }
    }
    for(int i=0;i<ans.size();i++){
        cout<<ans[i]<<" ";
    }
    cout<<endl;
}
int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        solve();
    }
}