pku1376 Robot

第一道A*

 想知道自己的启发函数有没有错的话，把函数返回值设为0再交上去看能不能通过就行了

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

#define MAXN 26001
#define tile(x,y) ((x-1)*m+y)
#define tile_x(t) (t/m+1)
#define tile_y(t) (t%m)
#define hamilton(s) ((abs(tile_x(s)-tile_x(ed))+abs(tile_y(s)-tile_y(ed)))/3)


int graph[55][55],n,m,g[MAXN],mk[MAXN],st,ed,s,x,y,op,ns,nop,f[MAXN];
char dir[5];

class CP{
public:
    int operator()(int t1,int t2){
        return f[t1]>f[t2];
    }
};

int astar(){
    int i;

    f[0]=-1;
    memset(mk,0,sizeof(mk));//0：未入队； 1：在open队中； 2：在closed队中
    priority_queue<int,vector<int>,CP > qu;

    g[st]=0;
    f[st]=g[st]+hamilton(st/10);
    qu.push(st);
    mk[st]=1;

    while(!qu.empty()){
        s=qu.top();
        qu.pop();

        op=s%10;
        x=tile_x(s/10);
        y=tile_y(s/10);

        if(s/10==ed)
            return g[s];
        mk[s]=2;

        nop=(op+1)%4;
        ns=s/10*10+nop;
        if(mk[ns]==0){
            g[ns]=g[s]+1;
            f[ns]=f[s]+1;
            qu.push(ns);
            mk[ns]=1;
        }
        else if(mk[ns]==1){
            if(g[s]+1<g[ns]){
                g[ns]=g[s]+1;
                qu.push(0);//更新堆
                qu.pop();
            }
        }


        nop=(op+3)%4;
        ns=s/10*10+nop;
        if(mk[ns]==0){
            g[ns]=g[s]+1;
            f[ns]=f[s]+1;
            qu.push(ns);
            mk[ns]=1;
        }
        else if(mk[ns]==1){
            if(g[s]+1<g[ns]){
                g[ns]=g[s]+1;
                qu.push(0);
                qu.pop();
            }
        }

        for(i=1;i<=3;i++){
            if(op==0)
                x--;
            if(op==1)
                y++;
            if(op==2)
                x++;
            if(op==3)
                y--;

            if(x<=1 || x>=n || y<=1 || y>=m || graph[x][y]==1)
                break;

            ns=tile(x,y);
            ns=ns*10+op;
            if(mk[ns]==0){
                g[ns]=g[s]+1;
                f[ns]=g[ns]+hamilton(ns/10);
                qu.push(ns);
                mk[ns]=1;
            }
            else if(mk[ns]==1){
                if(g[s]+1<g[ns]){
                    g[ns]=g[s]+1;
                    qu.push(0);
                    qu.pop();
                }
            }
        }
    }
    return -1;
}


int main(){
    int i,j,tmp,x,y;
    while(scanf("%d%d",&n,&m) && n && m){
        memset(graph,0,sizeof(graph));
        n++;m++;
        for(i=2;i<=n;i++){
            for(j=2;j<=m;j++){
                scanf("%d",&tmp);
                if(tmp)
                    graph[i][j]=graph[i-1][j]=graph[i][j-1]=graph[i-1][j-1]=1;
            }
        }

        /*
        printf("\n");
        for(i=1;i<=n;i++){
            for(j=1;j<=m;j++)
                printf("%d ",graph[i][j]);
            printf("\n");
        }
        printf("\n");*/


        scanf("%d%d",&x,&y);
        x++;y++;
        st=tile(x,y);
        scanf("%d%d",&x,&y);
        x++;y++;
        ed=tile(x,y);

        scanf("%s",dir);

        if(st==ed)
            printf("0\n");
        else{
            if(dir[0]=='n')
                st=st*10;
            if(dir[0]=='e')
                st=st*10+1;
            if(dir[0]=='s')
                st=st*10+2;
            if(dir[0]=='w')
                st=st*10+3;
            printf("%d\n",astar());

        }
    }
    return 0;
}