POJ 3349 Snowflake Snow Snowflakes

解题思路:hash

#include <iostream>
using namespace std;
#define MAX_N 87719

struct node{
    node():next(0){}
    int arm[6];
    node *next;
}snow[MAX_N];

int main()
{
    int hash,n,i,j,k,t[6];
    node *cur,*pre;
    bool isFind;
    scanf("%d", &n);
    for (i=0,isFind=false;i<n;i++)
    {
        scanf("%d %d %d %d %d %d",t,t+1,t+2,t+3,t+4,t+5);
        if(isFind)continue;
        hash = (t[0]^t[1]^t[2]^t[3]^t[4]^t[5])%MAX_N;
        cur=snow[hash].next;pre=&snow[hash];
        while (cur&&!isFind)
        {
            for (j=0;(j<6)&&!isFind;j++)
            {
                for(k=0;k<6;k++)
                    if(t[(k+j)%6]!=cur->arm[k])break;
                if(k==6){isFind=true;break;}
                for(k=0;k<6;k++)
                    if(t[(6+j-k)%6]!=cur->arm[k])break;
                if(k==6)isFind=true;
            }
            pre=cur,cur=cur->next;
        }
        if(!isFind){node *temp=new node();memcpy(temp->arm,t,sizeof(t));pre->next=temp;}
    }
    isFind ? printf("Twin snowflakes found.\n"):printf("No two snowflakes are alike.\n");
    return 0;
}