hdu acm 1016

那个 i ，我开始的时候定义成全局变量了，后来一直错，哈哈哈哈哈哈。

#include <stdio.h>
#include <string.h>

int prime[40] = {0,1,1,1,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0};
int visited[21], a[21], n, num;

void dfs(int num) {
	
	if(num == n && prime[a[num-1] + a[0]]) {
		for(int i=0; i<num-1; i++)
			printf("%d ", a[i]);
		printf("%d\n", a[num-1]);
	} else {
		for(int i=2; i<=n; i++) {
			if(!visited[i]) {
				if(prime[i + a[num-1]]) {
					visited[i] = 1;
					a[num] = i;
					dfs(num + 1);
					visited[i] = 0;
				}
			}
		}
	}
	
}

int main() {
	
	num = 0;
	while(~scanf("%d", &n)) {
		num ++;
		printf("Case %d:\n", num);
		memset(visited, 0, sizeof(visited));
		a[0] = 1;
		dfs(1);
		printf("\n");
	}
	
	return 0;
}