pruning.cpp

#pragma GCC optimize("Ofast")
#pragma comment(linker, "/stack:200000000")
#include <iostream>
#include <map>
#include <vector>
#include <cmath>
#include <algorithm>
#include <string>
#include <cmath>
#include <set>
#include <iomanip>
#include <ctime>
#include <cstring>
#include <map>
 
using namespace std;
 
const int N = 5100;
const int MOD = 1e9 + 7;
 
vector <int> now;
set <vector<int>> vis;
 
void cur(vector <int> stuff) {
	if (stuff.empty()) {
		reverse(now.begin(), now.end());
		for (auto x : now) {
			cout << x << "\n";
		}
		exit(0);
	}
	if (vis.count(stuff)) {
		return;
	}
	vis.insert(stuff);
	vector <int> check = stuff;
	sort(check.begin(), check.end());
	for (int i = 0; i < check.size(); ++i) {
		if (check[i] > i + 1) {
			return;
		}
	}
	for (int i = 0; i < stuff.size(); ++i) {
		if (stuff[i] > i + 1) {
			return;
		}
	}
	for (int i = stuff.size() - 1; i >= 0; --i) {
		if (stuff[i] == i + 1) {
			vector <int> stuff2 = stuff;
			stuff2.erase(stuff2.begin() + i);
			now.push_back(i + 1);
			cur(stuff2);
			now.pop_back();
		}
	}
}
 
int main() {
	::ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin >> n;
	vector <int> v(n);
	for (int i = 0; i < n; ++i) {
		cin >> v[i];
	}
	cur(v);
	cout << -1 << endl;
	return 0;
}