题解 | 全排列

// 全排列next_permutation
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    if (!(cin >> n)) return 0;
    vector<int> a(n);
    for(int i = 0; i < n ; i++) {
        a[i] = i + 1;
    }

    do {
        for (int i = 0; i < n; ++i) {
            if (i) cout << ' ';
            cout << a[i];
        }
        cout << endl;
    } while (next_permutation(a.begin(), a.end()));
    return 0;
}