C++ 代码

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int n, a[16], vis[16];
vector<int> ret;

void dfs(int idx){
    if(idx == n + 1){
        for(auto x : ret)
            cout << x << " ";
        cout << endl;
        return;
    }
    dfs(idx + 1);      //此数不选取

    if(idx > 1 && a[idx] == a[idx - 1] && vis[idx - 1] == 0) 
        return; //去掉重复序列

    ret.push_back(a[idx]);
    vis[idx] = 1;
    dfs(idx + 1);      //此数选取
    vis[idx] = 0;
    ret.pop_back();
}

int main()
{
    cin >> n;
    for(int i = 1; i <= n; ++ i) cin >> a[i];
    sort(a + 1, a + 1 + n);
    dfs(1);
    return 0;
}