CSU - 2061 Z‘s Coffee

最新推荐文章于 2021-06-25 22:04:33 发布

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最新推荐文章于 2021-06-25 22:04:33 发布

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原文链接：http://www.cnblogs.com/csu-lmw/p/9124456.html

本文介绍了一个有趣的算法问题：如何通过倒转不同容量的咖啡杯来获得目标毫升数的咖啡。利用广度优先搜索(BFS)算法，文章提供了一种解决方法，并详细展示了从初始状态到目标状态的操作步骤。

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Description

Z is crazy about coffee. One day he bought three cups of coffee. The first cup has a capacity of A ml, the second has B ml and the third has C ml. At the beginning, only the first cup is full of coffee, that is, Z only has A ml coffee and the other cups is empty. Because the cup has no scale, one operation of pouring coffee only stop until either one cup is full or empty. Z can only choose two cups to do the pouring operation. For some reasons, Z wants to get exactly D ml of coffee, and also he is so lazy that want the number of operations as least as possible. So he ask you for help.

Input

The first line is the case number T.

Each case has one line with four integers A B C D as mentioned above.

1 ≤ A, B, C ≤ 1000

1 ≤ D ≤ max(A, B, C)

1 ≤ T ≤ 100

Output

If he can get the exactly milliliter of coffee as he want, then print the least number of operation in a line.

And print the initial capacity of the three cups and then print the result after each operation line by line.

The print order should be the first cup, the second cup and the third cup.

If there are more than one operation schema, any of them will be accepted.

If he cannot get the exactly milliliter of coffee as he want , print "-1" without quotation.

Sample Input

1
12 8 5 10

Sample Output

Hint

Source

Author

周杰辉

设当前每杯的容量为x, y, z，因为x + y + z = A 则可以枚举i, j，将第i杯中的咖啡倒入第j杯如果满足条件，设倒入后的状态为x′,y′,z′ 判断其中是否有D，并记录其前驱为保证操作最少，用BFS扩展即可

#include<stdio.h>
#include<queue>
#include<iostream>
#include<set>
#include<vector>
#include<algorithm>
using namespace std;
const int MAXN = 1e6 + 5;
struct node{
	int cup[3],stp;
	int hash(){ return cup[0] * 1001 * 1001 + cup[1] * 1001 + cup[2]; }
	void print(){ printf("%d %d %d\n", cup[0], cup[1], cup[2]); }
};
queue<node>q;
set<int>se;
vector<node>ve;
node Q[MAXN];
int pre[MAXN];
int cup[3], d;
int bfs()
{
	int l = 0,r=0;
	node tmp;
	tmp.cup[0] = cup[0]; tmp.cup[1] = tmp.cup[2]=tmp.stp = 0;
	Q[++r] = tmp;
	se.insert(tmp.hash());
	while (l<r)
	{
		node u = Q[++l];
		for (int i = 0; i < 3;i++)
			if (u.cup[i])//对每个杯子
			{
				for (int j = 0; j < 3;j++)
					if (i != j&&u.cup[j] != cup[j])//不同杯子 也没有满
					{
						node v = u;
						if (v.cup[i] + v.cup[j]>cup[j])
						{
							v.cup[i] = v.cup[i] - (cup[j] - v.cup[j]);
							v.cup[j] = cup[j];
						}
						else
						{
							v.cup[j] += v.cup[i];
							v.cup[i] = 0;
						}
						v.stp = u.stp + 1;
						int hash = v.hash();
						if (!se.count(hash))//记录是否出现过该情况
						{
							se.insert(hash);
							Q[++r] = v;
							pre[r] = l;
							for (int k = 0; k < 3; k++)
							{
								if (v.cup[k] == d)return r;
							}
						}
					}
			}
	}
	return -1;
}
int main()
{
	int T;
	while (~scanf("%d", &T))
	{
		while (T--)
		{
			while (!q.empty())
				q. pop();
			scanf("%d %d %d %d", &cup[0], &cup[1], &cup[2],&d);
			se.clear();
			int ans = bfs();
			if (ans == -1)
			{
				printf("-1\n");
				continue;
			}
			int cnt = Q[ans].stp;
			ve.clear();
			for (int i = ans; i; i = pre[i])
				ve.push_back(Q[i]);
			reverse(ve.begin(), ve.end());
			printf("%d\n", cnt);
			for (int i = 0; i < ve.size(); i++)
			{
				printf("%d %d %d\n", ve[i].cup[0], ve[i].cup[1], ve[i].cup[2]);
			}
		}
	}

	return 0;
}

转载于:https://www.cnblogs.com/csu-lmw/p/9124456.html