题目大意：就是给你2个杯子和一瓶水，问如何将这瓶水二等分，并且输出最少的倒水次数

解题大意：最终的结果一定是最大的杯子和第二大的杯子各放一半水。然后每一次三个瓶子的装水情况下一步如何倒水一共有六种倒法，然后bfs模拟这个倒水，记得用一个数组纪录倒水后各个瓶子的装水情况。

AC代码如下：

#include<stdio.h>
#include<string.h>
#include<queue>
#include<math.h>
#include<iostream>
#include<algorithm>
using namespace std;

struct node
{
	int a,b,c,step;
};

int a,b,c,vis[110][110];
queue<node> Q;

int bfs()
{
	node now,xia;
	int i;
	while(!Q.empty())
		Q.pop();
	now.a=a;
	now.b=0;
	now.c=0;
	now.step=0;
	vis[now.a][now.b]=1;
	Q.push(now);
	while(!Q.empty())
	{
		now=Q.front();
		Q.pop();
		if(now.a==a/2 && now.b==a/2)
			return now.step;
		if(now.a && now.b<b)
		{
			if(now.a>=b-now.b)
			{
				xia.a=now.a-(b-now.b);
				xia.b=b;
				xia.c=now.c;
			}
			else
			{
				xia.a=0;
				xia.b=now.b+now.a;
				xia.c=now.c;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
		if(now.a && now.c<c)
		{
			if(now.a>=c-now.c)
			{
				xia.a=now.a-(c-now.c);
				xia.b=now.b;
				xia.c=c;
			}
			else
			{
				xia.a=0;
				xia.b=now.b;
				xia.c=now.c+now.a;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
		if(now.b && now.c<c)
		{
			if(now.b>=c-now.c)
			{
				xia.a=now.a;
				xia.b=now.b-(c-now.c);
				xia.c=c;
			}
			else
			{
				xia.a=now.a;
				xia.b=0;
				xia.c=now.c+now.b;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
		if(now.b && now.a<a)
		{
			if(now.b>=a-now.a)
			{
				xia.a=a;
				xia.b=now.b-(a-now.a);
				xia.c=now.c;
			}
			else
			{
				xia.a=now.a+now.b;
				xia.b=0;
				xia.c=now.c;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
		if(now.c && now.a<a)
		{
			if(now.c>=a-now.a)
			{
				xia.a=a;
				xia.b=now.b;
				xia.c=now.c-(a-now.a);
			}
			else
			{
				xia.a=now.a+now.c;
				xia.b=now.b;
				xia.c=0;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
		if(now.c && now.b<b)
		{
			if(now.c>=b-now.b)
			{
				xia.a=now.a;
				xia.b=b;
				xia.c=now.c-(b-now.b);
			}
			else
			{
				xia.a=now.a;
				xia.b=now.b+now.c;
				xia.c=0;
			}
			xia.step=now.step+1;
			if(!vis[xia.a][xia.b])
			{
				vis[xia.a][xia.b]=1;
				Q.push(xia);
			}
		}
	}
	return 0;
}

int main()
{
	int cnt;
	while(cin>>a>>b>>c && a+b+c)
	{
		memset(vis,0,sizeof(vis));
		if(a%2)
		{
			cout<<"NO"<<endl;
			continue;
		}
		if(c>b)
			cnt=c,c=b,b=cnt;
		cnt=bfs();
		if(!cnt)
			cout<<"NO"<<endl;
		else
			cout<<cnt<<endl;
	}
	return 0;
}