POJ 3414 Pots(BFS 倒水)

题意 你有两个容积分别为a,b杯子 你每次可以将某个杯子中的水倒满或者倒掉或者倒到另一个杯子 问能否通过这两个杯子量出c容量的水

和上一个倒可乐问题类似 只是这个操作更多了点 将两个杯子中各含有的水作为状态 每出队列一个状态 将所有可能到达的状态入队 直到有一个杯子里面水的体积为c 打印路径直接递归就行了

#include <map>#include <cstdio>#include <cstring>using namespace std;const int N = 105;int a, b, c, t, le, ri, v[N][N];int x[N * N], p[N * N], op[N * N], d[N * N];pair<int, int> q[N * N];void check(int i, int j, int o, int k){if(v[i][j]) return;v[i][j] = 1, p[ri] = le;op[ri] = o, x[ri] = k, d[ri] = d[le] + 1;q[ri++] = make_pair(i, j);}int bfs(){int ca, cb = le = ri = 0;q[ri++] = make_pair(0, 0);memset(v, 0, sizeof(v)), v[0][0] = 1;while(le < ri){ca = q[le].first, cb = q[le].second;if(ca == c || cb == c) return le;check(a, cb, 1, 1);//FILL(1);check(ca, b, 1, 2);//FILL(2);check(0, cb, 2, 1);//DROP(1);check(ca, 0, 2, 2);//DROP(2);if(ca > b – cb) check(ca – b + cb, b, 3, 1);else check(0, ca + cb, 3, 1);//POUR(1,2);if(cb > a – ca) check(a, cb – a + ca, 3, 2);else check(ca + cb, 0, 3, 2);//POUR(2,1);++le;}return 0;}void print(int k){if(p[k] > 0) print(p[k]);if(op[k] == 1) printf("FILL(%d)\n", x[k]);if(op[k] == 2) printf("DROP(%d)\n", x[k]);if(op[k] == 3) printf("POUR(%d,%d)\n", x[k], 3 – x[k]);}int main(){int ans;while(~scanf("%d%d%d", &a, &b, &c)){if(ans = bfs())printf("%d\n",d[ans]), print(ans);else puts("impossible");}return 0;}

Pots

Description

You are given two pots, having the volume ofAandBliters respectively. The following operations can be performed:

FILL(i) fill the poti(1 ≤i≤ 2) from the tap;DROP(i) empty the potito the drain;POUR(i,j) pour from potito potj; after this operation either the potjis full (and there may be some water left in the poti), or the potiis empty (and all its contents have been moved to the potj).

Write a program to find the shortest possible sequence of these operations that will yield exactlyCliters of water in one of the pots.

Input

On the first and only line are the numbersA,B, andC. These are all integers in the range from 1 to 100 andC≤max(A,B).

Output

The first line of the output must contain the length of the sequence of operationsK. The followingKlines must each describe one operation. If there are several sequences of minimal length, output any one of them. If the desired result can’t be achieved, the first and only line of the file must contain the word ‘impossible’.

Sample Input

3 5 4

Sample Output

6FILL(2)POUR(2,1)DROP(1)POUR(2,1)FILL(2)POUR(2,1)

,风景如何,其实并不重要。重要的是,你在我的身边。

POJ 3414 Pots(BFS 倒水)

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