uva1600 Patrol Robot 巡逻机器人(BFS)

</pre>Description<div class="textBG" style="border-width: 2px; border-style: dotted; padding: 10px; font-family: 'times new roman'; font-size: 17px; background-color: rgb(234, 235, 255);"><span style="float: right;"><a target=_blank style="color: blue; text-decoration: none;" href="http://7xjob4.com1.z0.glb.clouddn.com/1e64a3999d53f31d7746044a838fd900" target="_blank"><img width="100" height="26" title="Download as PDF" alt="Download as PDF" src="http://uva.onlinejudge.org/components/com_onlinejudge/images/button_pdf.png" border="0" /></a></span> <div style="clear: both;"></div><p style="margin-top: 0px; margin-bottom: 0pt;">A robot has to patrol around a rectangular area which is in a form of <span class="MATH"><em>m</em><tt>x</tt><em>n</em></span> grid (<span class="MATH"><em>m</em></span> rows and <span class="MATH"><em>n</em></span> columns). The rows are labeled from 1 to <span class="MATH"><em>m</em></span>. The columns are labeled from 1 to <span class="MATH"><em>n</em></span>. A cell <span class="MATH">(<em>i</em>, <em>j</em>)</span> denotes the cell in row <span class="MATH"><em>i</em></span> and column <span class="MATH"><em>j</em></span> in the grid. At each step, the robot can only move from one cell to an adjacent cell, i.e. from <span class="MATH">(<em>x</em>, <em>y</em>)</span> to <span class="MATH">(<em>x</em> + 1, <em>y</em>)</span>, <span class="MATH">(<em>x</em>, <em>y</em> + 1)</span>, <span class="MATH">(<em>x</em> - 1, <em>y</em>)</span> or <span class="MATH">(<em>x</em>, <em>y</em> - 1)</span>. Some of the cells in the grid contain obstacles. In order to move to a cell containing obstacle, the robot has to switch to turbo mode. Therefore, the robot cannot move continuously to more than <span class="MATH"><em>k</em></span> cells containing obstacles.</p><p style="margin-top: 0px; margin-bottom: 0pt;">Your task is to write a program to find the shortest path (with the minimum number of cells) from cell (1, 1) to cell <span class="MATH">(<em>m</em>, <em>n</em>)</span>. It is assumed that both these cells do not contain obstacles.</p><p style="margin-top: 0px; margin-bottom: 0pt;"></p><h2 style="margin-bottom: 0px;"><a target=_blank name="t0"></a><span style="color: rgb(255, 0, 0); font-size: 18px;"><a target=_blank name="SECTION0001001000000000000000" style="color: blue; text-decoration: none;" href="http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=49764" target="_blank">Input</a> </span></h2><p style="margin-top: 0px; margin-bottom: 0pt;">The input consists of several data sets. The first line of the input file contains the number of data sets which is a positive integer and is not bigger than 20. The following lines describe the data sets.</p><p style="margin-top: 0px; margin-bottom: 0pt;">For each data set, the first line contains two positive integer numbers <span class="MATH"><em>m</em></span> and <span class="MATH"><em>n</em></span> separated by space <span class="MATH">(1<img width="18" height="31" align="MIDDLE" alt="$ \le$" src="" border="0" /><em>m</em>, <em>n</em><img width="18" height="31" align="MIDDLE" alt="$ \le$" src="" border="0" />20)</span>. The second line contains an integer number <span class="MATH"><em>k</em></span><span class="MATH">(0<img width="18" height="31" align="MIDDLE" alt="$ \le$" src="" border="0" /><em>k</em><img width="18" height="31" align="MIDDLE" alt="$ \le$" src="" border="0" />20)</span>. The <span class="MATH"><em>i</em><sup>th</sup></span> line of the next <span class="MATH"><em>m</em></span> lines contains <span class="MATH"><em>n</em></span> integer <span class="MATH"><em>a</em><sub>ij</sub></span> separated by space <span class="MATH">(<em>i</em> = 1, 2,..., <em>m</em>;<em>j</em> = 1, 2,..., <em>n</em>)</span>. The value of <span class="MATH"><em>a</em><sub>ij</sub></span> is <tt>1</tt> if there is an obstacle on the cell <span class="MATH">(<em>i</em>, <em>j</em>)</span>, and is <tt>0</tt> otherwise.</p><p style="margin-top: 0px; margin-bottom: 0pt;"></p><h2 style="margin-bottom: 0px;"><a target=_blank name="t1"></a><span style="color: rgb(255, 0, 0); font-size: 18px;"><a target=_blank name="SECTION0001002000000000000000" style="color: blue; text-decoration: none;" href="http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=49764" target="_blank">Output</a> </span></h2><p style="margin-top: 0px; margin-bottom: 0pt;">For each data set, if there exists a way for the robot to reach the cell <span class="MATH">(<em>m</em>, <em>n</em>)</span>, write in one line the integer number <span class="MATH"><em>s</em></span>, which is the number of moves the robot has to make; <tt>-1</tt> otherwise.</p><p style="margin-top: 0px; margin-bottom: 0pt;"></p><h2 style="margin-bottom: 0px;"><a target=_blank name="t2"></a><span style="color: rgb(255, 0, 0); font-size: 18px;"><a target=_blank name="SECTION0001003000000000000000" style="color: blue; text-decoration: none;" href="http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=49764" target="_blank">Sample Input</a> </span></h2><p style="margin-top: 0px; margin-bottom: 0pt;"></p><pre style="white-space: pre-wrap; -ms-word-wrap: break-word;">3 2 5 0 0 1 0 0 0 0 0 0 1 0 4 6 1 0 1 1 0 0 00 0 1 0 1 10 1 1 1 1 00 1 1 1 0 02 2 0 0 1 1 0

Sample Output 

7 10 -1

代码如下 ：（不要直接复制 有些许不一样）

#include<iostream>#include<cstdio>#include<cstring>#include<queue>using namespace std;int maze[22][22];int n,m,ax,ay,gx,gy,k,T;struct node{    int x;    int y;    int num;}a,b;int j;int dx[]={0,1,0,-1};int dy[]={1,0,-1,0};int d[22][22];int vis[22][22];int bfs(){j=0;memset(d,0,sizeof(d));memset(vis,0,sizeof(vis)); a.x=1;a.y=1;a.num=0;    queue<node>q;    q.push(a);    while(!q.empty())    {        a=q.front();        q.pop();        if(a.x==m&&a.y==n)                    return d[a.x][a.y];        for(int i=0;i<4;i++)        {            b.x=a.x+dx[i];            b.y=a.y+dy[i];            b.num=a.num;            if(maze[b.x][b.y]==1)            {                a.num++;                b.num=a.num;            }            if(maze[b.x][b.y]==0)            b.num=0;            if(b.x>0&&b.x<=m&&b.y>0&&b.y<=n&&vis[b.x][b.y]==0&&b.num<=k)            {             d[b.x][b.y]=d[a.x][a.y]+1;                    vis[b.x][b.y]=-1;                    q.push(b);                           j++;              if(j>m*n)            return -1;                       }        }    }    return -1;}int main(){while(~scanf("%d",&t)&&t){    while(t--){       scanf("%d%d",&m,&n);                       scanf("%d",&k);        for(int i=1;i<=m;i++)        {            for(int j=1;j<=n;j++)            {                scanf("%d",&maze[i][j]);            }        }        int t=bfs();       cout<<t<<endl;      }    }    return 0;}