ZOJ 3652 Maze 模拟,bfs,读题 难度:2

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=4842

要注意题目中两点:

1.在踏入妖怪控制的区域那一刹那,先减行动力,然后才能杀妖怪

2.在妖怪控制区域行动力也会恢复

3.妖怪也许不在自己的控制区域

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>

using namespace std;
const int maxn=100;
const int dx[4] = {0,0,-1,1};
const int dy[4] = {1,-1,0,0};
int n,m,l,k,sx,sy,tx,ty;
int maz[maxn][maxn];
int mon[6][2];

int vis[maxn][maxn][maxn];
int ind[maxn][maxn];
struct P{
    int x,y,sta,r;
    P(){x = y = sta = r = 0;}
    P(int _x,int _y,int _sta,int _r){
        x = _x;
        y = _y;
        sta = _sta;
        r = _r;
    }
    bool operator <(P p2)const {
        if(vis[x][y][sta] != vis[p2.x][p2.y][p2.sta])
            return vis[x][y][sta] > vis[p2.x][p2.y][p2.sta];
        return r < p2.r;
    }
};
int ok(int x,int y,int sta){
    if(x < 1 || y < 1 || x > n || y > m)return -1;
    int ki = maz[x][y];
    if(ki == -1)return -1;
    if(ki > 0){
        if(sta & (1 << (ki-1)))return 1;
        return 0;
    }
    return 1;
}
priority_queue <P> que;
int bfs(){
    memset(vis ,-1, sizeof vis);
    vis[sx][sy][0] = 0;
    que.push(P(sx,sy,0,0));
    while(!que.empty()){
        P tp=que.top();que.pop();
       // printf("pop  x: %d y: %d sta: %d step %d turn %d
",tp.x,tp.y,tp.sta,tp.r,vis[tp.x][tp.y][tp.sta]);
        if(tx == tp.x && ty == tp.y)return vis[tx][ty][tp.sta];
        for(int i = 0;i < 4;i++){
            int tmpx = tp.x + dx[i];
            int tmpy = tp.y + dy[i];
            int sta = tp.sta;
            if(ind[tmpx][tmpy] != 0)sta |= (1 << (ind[tmpx][tmpy] - 1));
            if(ok(tmpx,tmpy,tp.sta) >= 0 && vis[tmpx][tmpy][sta] == -1){
                if(tp.r == 0){
                    vis[tmpx][tmpy][sta] = vis[tp.x][tp.y][tp.sta] + 1;
                   // printf("push x: %d y: %d sta: %d step %d turn %d
",
                    //       tmpx,tmpy,sta,(ok(tmpx,tmpy,sta)==0?0:l-1),vis[tp.x][tp.y][tp.sta]+1);
                    que.push(P(tmpx,tmpy,sta,(ok(tmpx,tmpy,tp.sta) == 0?0:l-1)));
                }
                else {
                    vis[tmpx][tmpy][sta] = vis[tp.x][tp.y][tp.sta];
                    //printf("push x: %d y: %d sta: %d step %d turn %d
",
                      //     tmpx,tmpy,sta,(ok(tmpx,tmpy,sta)==0?0:tp.r-1),vis[tp.x][tp.y][tp.sta]);
                    que.push(P(tmpx,tmpy,sta,(ok(tmpx,tmpy,tp.sta) == 0?0:tp.r-1)));
                }
            }
        }
    }
    return -1;
}

int main(){
    while(scanf("%d%d%d",&n,&m,&l) == 3){
        while(!que.empty())que.pop();
        memset(ind,0,sizeof ind);
        for(int i = 1;i <= n;i++){
            for(int j = 1;j <= m;j++){
                scanf("%d",maz[i]+j);
            }
        }
        scanf("%d",&k);
        for(int i = 1;i <= k;i++){
            scanf("%d%d",mon[i],mon[i] + 1);
            ind[mon[i][0]][mon[i][1]]=i;
        }
        scanf("%d%d%d%d",&sx,&sy,&tx,&ty);
        int ans = bfs();
        if(ans < 0){
            puts("We need God's help!");
        }
        else {
            printf("%d
",ans);
        }
    }
    return 0;
}