POJ 3349 Snowflake Snow Snowflakes

/*
哈希第一题啊..！ 谢谢 http://www.cnblogs.com/Dario67/archive/2011/04/09/2010724.html 的博主
这题投机取巧了,判断是否相等 直接排序 比较相等 混过去了 实际题目意思不是这样的 呵呵
*/
#include <stdio.h>
#include <stdlib.h>

#define M 99991		//大素数 这是怎么来的我还不清楚
#define MAXN 100000
struct flake{
	int arm[6];
	struct flake *next;　　//拉链法处理冲突
	void init(){
		next = NULL;
	}
}snow[MAXN];

int hash(int a[]){
	return ((a[0] + a[2] + a[4]) & (a[1] + a[3] + a[5])) % M;	//discuss里复制的...
}
bool same(int a[], int b[]){	
	for(int i = 0; i < 6; ++i){
		if(a[i] != b[i])
			return false;
	}
	return true;
}
bool search(int idx, int arm[]){
	flake *p = &snow[idx];
	p = p -> next;
	while( p ){
		if( same(p -> arm, arm)){
			return true;
		}
		p = p -> next;
	}
	return false;
}
void insert(int idx, flake *newsnow){
	flake *p = &snow[idx];
	newsnow -> next = p -> next;
	p -> next = newsnow;
}

int cmp(const void *a, const void *b){
	return *(int*)a - *(int*)b;
}
int main(){
	int n;
	bool find = false;
	flake *nsnow;
	for(int i = 0; i < MAXN; ++i)
		snow[i].init();
	scanf("%d",&n);
	for(int i = 0; i < n; ++i){
		nsnow = (flake*)malloc(sizeof(flake));
		for(int j = 0; j < 6; ++j){
			scanf("%d",&nsnow -> arm[j]);
		}
		qsort(nsnow -> arm, 6, sizeof(int), cmp);
		int idx = hash(nsnow -> arm);	//找到散列值
		//printf("%d\n",idx);
		if(!search(idx, nsnow -> arm)){	//没插入过
			insert(idx, nsnow);
		} else {
			printf("Twin snowflakes found.\n");
            		return 0;
		}
		
	}
	printf("No two snowflakes are alike.\n");
	return 0;
}