nyoj 635 Oh, my goddess 【bfs(简单题)】

Oh, my goddess

时间限制：3000 ms  |  内存限制：65535 KB

难度：3

描述

Shining Knight is the embodiment of justice and he has a very sharp sword can even cleavewall. Many bad guys are dead on his sword.

One day, two evil sorcerer cgangee and Jackchess decided to give him some colorto see. So they kidnapped Shining Knight's beloved girl--Miss Ice! They built a M x Nmaze with magic and shut her up in it.

Shining Knight arrives at the maze entrance immediately. He can reach any adjacent emptysquare of four directions -- up, down, left, and right in 1 second. Or cleave one adjacent wall in 3

seconds, namely,turn it into empty square. It's the time to save his goddess! Notice: ShiningKnight won't leave the maze before he find Miss Ice.

输入

The input consists of blocks of lines. There is a blank line between two blocks.

The first line of each block contains two positive integers M <= 50 and N <= 50separated by one space. In each of the next M lines there is a string of length N contentsO and #.

O represents empty squares. # means a wall.

At last, the location of Miss Ice, ( x, y ). 1 <= x <= M, 1 <= y <= N.

(Shining Knight always starts at coordinate ( 1, 1 ). Both Shining and Ice's locationguarantee not to be a wall.)

输出

The least amount of time Shining Knight takes to save hisgoddess in one line.

样例输入

3 5O##########O#O#3 4

样例输出

14

来源

郑大第六届校赛

上传者

ACM_赵铭浩

 

思路：

        写这一道题的时候，不知道怎么回事，一直出错！然后直接将结果在bfs函数里面输出，却a了，然后又改成原来的，也对了，我也是无语了！

 

代码：

//这一道题感觉很简单，但是到现在为止，我也不知道哪把我坑那了，wa了好多遍！ #include <stdio.h>#include <string.h>#include <algorithm>#include <queue>#define INF 0x3f3f3f3fusing namespace std;char mp[55][55];int vis[55][55];int n,m;int x,y,ex,ey;int ans;int dx[4]={0,1,-1,0};int dy[4]={1,0,0,-1};struct node {int x,y,step;bool friend operator < (node a,node b){return a.step>b.step;} }a,temp;int judge(){if(temp.x<1||temp.x>n)return 0;if(temp.y<1||temp.y>m)return 0;if(vis[temp.x][temp.y]==1)return 0;if(temp.step>=ans) return 0;return 1;}void bfs(){a.x=x;a.y=y;a.step=0;priority_queue<node>q;q.push(a);memset(vis,0,sizeof(vis));vis[x][y]=1;while(!q.empty()){a=q.top();q.pop();for(int i=0;i<4;i++){temp.x=a.x+dx[i];temp.y=a.y+dy[i];if(mp[temp.x][temp.y]=='#')temp.step=a.step+4;elsetemp.step=a.step+1;if(judge()){if(temp.x==ex&&temp.y==ey){ans=temp.step;//printf("%d\n",temp.step);return;}q.push(temp);vis[temp.x][temp.y]=1;}}}}int main(){while(~scanf("%d%d",&n,&m)){ans=INF;//我也真是够了，这个竟然忘记写了！错了好长时间！ for(int i=1;i<=n;i++){scanf("%s",mp[i]+1);}x=1;y=1;scanf("%d%d",&ex,&ey);if(ex==x&&ey==y){printf("0\n");continue;}bfs();printf("%d\n",ans);}return 0;}