枚举排列

#include<iostream> 
#include<cstring>
#include<algorithm>
using namespace std;

const int n=3;
void print_permutation(int n,int* A,int ch){
    if(n==ch){
        for(int i=0;i<n;i++)
            printf("%d",A[i]);
        printf("\n");
    }
    else{
        for(int i=1;i<=n;i++){
            int ok=1;
            for(int j=0;j<ch;j++){
                if(A[j]==i)
                    ok=0; 
            }
            if(ok){
                A[ch]=i;
                print_permutation(n,A,ch+1);
            }
        }
    }
}
void STL_print_permutation(int n,int* A){
    for(int i=1;i<=n;i++)   A[i-1]=i;
    do{
        for(int i=0;i<n;i++)    printf("%d",A[i]);
        printf("\n");
    }while(next_permutation(A,A+n));
    return ;
}
int main(){
    int a[10];
    memset(a,0,sizeof(a));
    printf("My_permutation:\n");
    print_permutation(n,a,0);
    printf("STL_permutation:\n");
    STL_print_permutation(n,a);
    return 0;
}