HDU2425：Hiking Trip(BFS+优先队列)

给出一个地图，地图有四种路面，经过每种路面花费的时间不同，问从起点到终点所花费的最少时间是多少

把到各个点的花费存入队列中，然后弹出，即可得到最小 

Sample Input

4 6 1 2 10 T...TT TTT### TT.@#T ..###@ 0 1 3 0 4 6 1 2 2 T...TT TTT### TT.@#T ..###@ 0 1 3 0 2 2 5 1 3 T@ @. 0 0 1 1

 

Sample Output

Case 1: 14 Case 2: 8 Case 3: -1

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;
int x,y,v1,v2,v3,b,n,m;
int x1,x2,y1,y2;
int p[25][25];
int vis[25][25];
int v[5];
int dir[4][2] = {{1,0},{-1,0},{0,1},{0,-1}};
struct node
{
    int x,y,step;
    friend bool operator < (node a,node b)
    {
        return a.step > b.step;
    }
};

bool judge(int x,int y)
{
    if(x < 0 || y < 0 || x >= n || y >= m || p[x][y] < 0 || vis[x][y])
        return false;
    return true;
}

int work()
{
    priority_queue<node>que;
    node a,b;
    a.x=x1;
    a.y=y1;
    a.step = 0;
    que.push(a);
    memset(vis,0,sizeof(vis));
    vis[x1][y1] = 1;
    while(!que.empty())
    {
        a = que.top();
        que.pop();
        if(a.x == x2 && a.y == y2)
                return a.step;
        for(int i = 0;i < 4;i++)
        {
            b = a;
            b.x += dir[i][0];
            b.y += dir[i][1];
            if(!judge(b.x,b.y))
                continue;
            b.step  += v[p[b.x][b.y]];
            vis[b.x][b.y] = 1;
            que.push(b);
        }
    }
    return -1;
}

int main()
{
    int i,j,cas = 1;
    char s[1000];
    while(~scanf("%d%d",&n,&m))
    {
        scanf("%d%d%d",&v[3],&v[2],&v[1]);
        for(i = 0; i < n; i++)
        {
            scanf("%s",s);
            for(j = 0;s[j]; j++)
            {
                if(s[j]=='T') p[i][j] = 1;
                else if(s[j] == '.') p[i][j] = 2;
                else if(s[j] == '#') p[i][j] = 3;
                else if(s[j] == '@') p[i][j] = -1;
            }
        }
        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
        int ans = work();
        printf("Case %d: %d
",cas++,ans);
    }
    return 0;
}