三个水杯

时间限制：1000 ms | 内存限制：65535 KB

难度：4

描述

给出三个水杯，大小不一，并且只有最大的水杯的水是装满的，其余两个为空杯子。三个水杯之间相互倒水，并且水杯没有标识，只能根据给出的水杯体积来计算。现在要求你写出一个程序，使其输出使初始状态到达目标状态的最少次数。

输入

第一行一个整数N(0<N<50)表示N组测试数据
接下来每组测试数据有两行，第一行给出三个整数V1 V2 V3 (V1>V2>V3 V1<100 V3>0)表示三个水杯的体积。
第二行给出三个整数E1 E2 E3 （体积小于等于相应水杯体积）表示我们需要的最终状态

输出

每行输出相应测试数据最少的倒水次数。如果达不到目标状态输出-1

样例输入

样例输出

3
-1

来源

经典题目

广度优先搜索，貌似可以用A*，可惜不怎么会，以后试试。

# include <stdio.h>  
# include <stdlib.h>  
# include <string.h>  
# include <string>  
  
void check (int queue[], int x, int &tail) {  
    for (int i = 0; i <= tail; ++ i) {  
        if (queue[i] == x) {  
            return;  
        }  
    }  
    ++ tail;  
    //printf ("%d -> ", x);  
    queue[tail] = x;  
    return;  
}  
  
int getans(int to[], int i) {  
    if (i == to[1] * 10000 + to[2] * 100 + to[3]) return 1;  
    return 0;  
}  
  
int daoshui(int queue[], int &a, int &b, int to, int from[]) {  
    if (a) {  
        int t = from[to] - b;  
        if (t > a) {  
            b += a;  
            a = 0;  
            return 1;  
        }  
        else if (t) {  
            a -= t;  
            b += t;  
            return 1;  
        }  
    }  
    return 0;  
}  
  
int main () {  
    int n;  
    scanf ("%d", &n);  
    while (n --) {  
        int from[4];  
        int to[4];  
        scanf ("%d %d %d %d %d %d", &from[1], &from[2], &from[3], &to[1], &to[2], &to[3]);  
        int head = 0;  
        int tail = 0;  
        int step = 0;   
        int queue[100000];  
        queue[0] = from[1] * 10000;  
        int flag = 0;  
        if (queue[0] == to[1] * 10000 + to[2] * 100 + to[3]) {printf("0
");continue;}  
        while (head <= tail) {  
            ++ step;  
            //printf("******************************%d************************************
", step);  
            int size = tail - head;  
            for (int i = head; i <= head + size; ++ i) {  
                int a, b, c;  
                //printf ("|%d|", queue[i]);  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, a, b, 2, from)) {  
                    //printf ("(a -> b)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, a, c, 3, from)) {  
                    //printf ("(a -> c)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, b, a, 1, from)) {  
                    //printf ("(b -> a)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, b, c, 3, from)) {  
                    //printf ("(b -> c)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, c, a, 1, from)) {  
                    //printf ("(c -> a)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
                a = queue[i] / 10000; b = queue[i] % 10000 / 100; c = queue[i] % 100;  
                if (daoshui(queue, c, b, 2, from)) {  
                    //printf ("(c -> b)");  
                    check(queue, a * 10000 + b * 100 + c, tail);  
                }  
            }  
            //printf ("
****************************************************************");  
            head += size + 1;  
            for (int i = head; i <= tail; ++ i) {  
                if (getans(to, queue[i])) {  
                    printf ("%d
", step);  
                    flag = 1;  
                    break;  
                }  
            }  
            if (flag) break;  
        }  
        //printf("
");  
        if (!flag) printf ("-1
");  
    }  
    return 0;  
}