题解

#include <iostream>
#include <vector>
#include <unordered_map>
#include <string>
using namespace std;

void solve() {
    int n;
    cin >> n;
    vector<int> a(n);
    unordered_map<int, int> first_pos, last_pos;
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        if (first_pos.find(a[i]) == first_pos.end()) {
            first_pos[a[i]] = i;
        }
        last_pos[a[i]] = i;
    }
    
    vector<int> ans(n, 0);
    int min_first = n, max_last = -1;    
    for (int m = 1; m <= n; ++m) {
        min_first = min(min_first, first_pos[m]);
        max_last = max(max_last, last_pos[m]);
        
        if (max_last - min_first + 1 == m) {
            ans[m - 1] = 1; 
        }
    }
    
    for (int num : ans) {
        cout << num;
    }
    cout << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int T;
    cin >> T;
    while (T--) {
        solve();
    }
    return 0;
}