http://poj.org/problem?id=1979
image.png
image.png
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典型的dfs
注意：将走过的路设置为"#",不需要还原回去。
//
// Created by ljs on 2018/8/27.
//
#include <iostream>
using namespace std;
int m, n;
int dir[4][4] = {{-1, 0}, {0, 1},{1, 0}, {0, -1}};
int count = 0;
void dfs(char maze[21][21], int x, int y){
count++;
for(int i = 0; i < 4; i++){
int xx = x + dir[i][0];
int yy = y + dir[i][1];
if(xx >= 0 && xx <= m-1 && yy >= 0 && yy <= n-1 && maze[xx][yy] == '.'){
maze[xx][yy] = '#';
dfs(maze,xx, yy);
}
}
}
int main(){
while(1){
cin>>n>>m;
if(m == 0 && n == 0) break;
int startx, starty;
char maze[21][21];
for(int i = 0; i < m; i++){
for(int j = 0; j < n; j++){
cin>>maze[i][j];
if(maze[i][j] == '@'){
startx = i;
starty = j;
}
}
}
maze[startx][starty] == '#';
count = 0;
dfs( maze, startx, starty);
cout<<count<<endl;
}
}
