题解 | 火车进站

#include <iostream>
#include<vector>
#include <stack>
#include <algorithm>
#include <numeric>

using namespace std;
int n;
int id[11];
vector<int> arr;

bool cmp() {
    stack<int> s;
    int j = 0;
    for (int i = 0; i < n; ++i) {
        s.push(id[i]);
        while (!s.empty() && s.top() == arr[j]) {
            s.pop();
            j++;
        }
    }
    return s.empty() && j == n;
}
int main() {
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> id[i];
    }
    arr.resize(n);
    iota(arr.begin(),arr.end(),1);
    do {
        if (cmp()) {
            cout << arr[0];
            for (int i = 1; i < n; ++i)
                cout << ' ' << arr[i];
            cout << endl;
        }
    } while (next_permutation(arr.begin(),arr.end()));
    return 0;
}
// 64 位输出请用 printf("%lld")