poj1606

bfs

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#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

using namespace std;



#define maxn 105



struct Node

{

    int va, vb, step, pre, opr;

} q[maxn * maxn];



int a, b, c, l, r;

bool vis[maxn][maxn];

int stk[maxn * maxn], top;



void make(int va, int vb, int opr)

{

    if (vis[va][vb])

        return;

    vis[va][vb] = true;

    q[r].va = va;

    q[r].vb = vb;

    q[r].step = q[l].step + 1;

    q[r].opr = opr;

    q[r].pre = l;

    r++;

}



void output()

{

    top = 0;

    while (l != 0)

    {

        stk[top++] = q[l].opr;

        l = q[l].pre;

    }

    for (int i = top - 1; i >= 0; i--)

        switch (stk[i])

        {

        case 1:

            printf("fill A\n");

            break;

        case 2:

            printf("fill B\n");

            break;

        case 3:

            printf("empty A\n");

            break;

        case 4:

            printf("empty B\n");

            break;

        case 5:

            printf("pour B A\n");

            break;

        case 6:

            printf("pour A B\n");

            break;

        }

    printf("success\n");

}



void bfs()

{

    q[0].va = 0;

    q[0].vb = 0;

    q[0].step = 0;

    vis[0][0] = true;

    l = 0;

    r = 1;

    while (l != r)

    {

        if (q[l].vb == c)

        {

            output();

            return;

        }

        int xa, xb, x;

        xa = a;

        xb = q[l].vb;

        make(xa, xb, 1);

        xa = q[l].va;

        xb = b;

        make(xa, xb, 2);

        xa = 0;

        xb = q[l].vb;

        make(xa, xb, 3);

        xa = q[l].va;

        xb = 0;

        make(xa, xb, 4);

        x = min(a - q[l].va, q[l].vb);

        xa = q[l].va + x;

        xb = q[l].vb - x;

        make(xa, xb, 5);

        x = min(b - q[l].vb, q[l].va);

        xa = q[l].va - x;

        xb = q[l].vb + x;

        make(xa, xb, 6);

        l++;

    }

}



int main()

{

    //freopen("t.txt", "r", stdin);

    while (scanf("%d%d%d", &a, &b, &c) != EOF)

    {

        memset(vis, 0, sizeof(vis));

        bfs();

    }

    return 0;

}