位向量法生成所有子集

#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <cctype>
using namespace std;

int n = 4;

void (int *vis, int *a, int cur)
{
    if(cur == n){
        for(int i = 0; i < n; i++) if(vis[i]){
            printf("%d ", a[i]);
        }
        printf("n");
        return ;

    }
    vis[cur] = 1;//选第cur个元素
    print_subset(vis, a, cur + 1);
    vis[cur] = 0;//不选第cur个元素
    print_subset(vis, a, cur + 1);
}

int main()
{
    int vis[4] = {0};
    int a[4] = {1,2,3,4};
    print_subset(vis, a, 0);
    return 0;
}

输出：
1 2 3 4 
1 2 3 
1 2 4 
1 2 
1 3 4 
1 3 
1 4 
1 
2 3 4 
2 3 
2 4 
2 
3 4 
3 
4