Factorial de n (basado en DFS)

 

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int book[10];//判断是否走过该步 
int a[10];//存储走过的步 
int n;
void dfs(int step){
	if(step==n+1)
	{
		for(int i = 1;i<=n;i++)
			printf("%d",a[i]);
		printf("\n");
		return;
	}
	for(int i = 1;i<=n;i++){
		if(book[i]==0){
			a[step] = i;
			book[i] = 1;
			dfs(step+1);
			book[i]=0;
		}
	}
	return;
} 
int main(){
	scanf("%d",&n);
	dfs(1);
	return 0;
}