poj1979 Red And Black(DFS)

题目链接

http://poj.org/problem?id=1979

思路

floodfill问题，使用dfs解决

代码

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 20;
char maze

;
int visit

;
int dir[4][2] = {{-1, 0}, {0 ,1}, {1, 0}, {0, -1}};
int nums;
int w, h;

void dfs(int r, int c){
visit[r][c] = 1;
for(int i=0; i<4; i++){
int nextr = r + dir[i][0];
int nextc = c + dir[i][1];

if(nextr>=0 && nextr<h && nextc>=0 && nextc<w && maze[nextr][nextc]!='#' && !visit[nextr][nextc]){
visit[nextr][nextc] = 1;
nums++;
dfs(nextr, nextc);
}
}
}

int main(){
//freopen("poj1979.txt", "r", stdin);
int sr, sc;
while(cin>>w>>h && w && h){
nums = 1;
memset(visit, 0, sizeof(visit));
for(int i=0; i<h; i++){
for(int j=0; j<w; j++){
cin>>maze[i][j];
if(maze[i][j] == '@'){
sr = i;
sc = j;
}
}
}
dfs(sr, sc);
cout << nums <<endl;
}
return 0;
}