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 of A and B liters respectively. The following operations can be performed:

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

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

Input

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

Output

The first line of the output must contain the length of the sequence of operations K. The following K lines 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

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