ACM篇：POJ 3414 --Pots

一段通俗的代碼

#include <iostream>
#include <cstdio>
#include <queue>
using namespace std;

const int MAX = 100;
int a;
int b;
int aim;

struct Node
{
    int l;
    int r;
    int step;
    Node(int l=0, int r=0, int step=0)
    {
        this->l = l;
        this->r = r;
        this->step = step;
    }
};
struct Path
{
    int l;
    int r;
    int method;
    Path(int l=0, int r=0, int method=0)
    {
        this->l = l;
        this->r = r;
        this->method = method;
    }
};
queue<Node> q;
Path visit[MAX+2][MAX+2];

const char act[][10] = {"", "FILL(1)", "FILL(2)","DROP(1)","DROP(2)",
"POUR(1,2)", "POUR(2,1)"};
void _print(int l, int r)
{
    if (!l && !r)
        return;
    _print(visit[l][r].l, visit[l][r].r);
    printf("\n%s", act[visit[l][r].method]);
}
void _bfs()
{
    Node head;

    q.push(Node{0, 0, 0});
    visit[0][0] = Path{0, 0, -1};
    while (!q.empty())
    {
        head = q.front();
        q.pop();

        if (head.l == aim || head.r == aim)
        {
            printf("%d", head.step);
            _print(head.l, head.r);
            return; 
        }
        //  fill    1
        if (head.l < a && !visit[a][head.r].method)
        {
            q.push(Node{a, head.r, head.step+1});
            visit[a][head.r] = Path{head.l, head.r, 1};
        }
        //  fill    2
        if (head.r < b && !visit[head.l][b].method)
        {
            q.push(Node{head.l, b, head.step+1});
            visit[head.l][b] = Path{head.l, head.r, 2};
        }
        //  drop    1
        if (head.l && !visit[0][head.r].method)
        {
            q.push(Node{0, head.r, head.step+1});
            visit[0][head.r] = Path{head.l, head.r, 3};
        }
        //  drop    2
        if (head.r && !visit[head.l][0].method)
        {
            q.push(Node{head.l, 0, head.step+1});
            visit[head.l][0] = Path{head.l, head.r, 4};
        }
        //  pour    1   to   2
        if (head.l >= b - head.r)
        {
            if (!visit[head.l - b + head.r][b].method)
            {
                q.push(Node{head.l - b + head.r, b, head.step+1});
                visit[head.l - b + head.r][b] = Path{head.l, head.r, 5};
            }
        }
        else if (!visit[0][head.r + head.l].method)
        {
            q.push(Node{0, head.r + head.l, head.step+1});
            visit[0][head.l + head.r] = Path{head.l, head.r, 5};
        }
        //  pour    2   to  1
        if (head.r >= a - head.l)
        {
            if (!visit[a][head.r - a + head.l].method)
            {
                q.push(Node{a, head.r - a + head.l, head.step+1});
                visit[a][head.r - a + head.l] = Path{head.l, head.r, 6};
            }
        }
        else if (!visit[head.l + head.r][0].method)
        {
            q.push(Node{head.l + head.r, 0, head.step+1});
            visit[head.l + head.r][0] = Path{head.l, head.r, 6};
        }
    }
    printf("impossible");
}
int main()
{
    scanf("%d%d%d", &a, &b, &aim);
    _bfs();
    return 0;
}