ZOJ 2165 Red and Black

1.采用dfs：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
using namespace std;
char map[25][25];
int count = 1;
int r,c;
int dx[4] = {1,-1,0,0};
int dy[4] = {0,0,1,-1};
bool judge(int x,int y)
{
??? if(x<0 || x>= r || y < 0 ||y>=c)
??????? return 0;
??? return 1;
}
void dfs(int x,int y)
{
??? map[x][y] = '#';
??? int nx = 0;
??? int ny = 0;
??? for(int i = 0 ; i < 4; i++)
??? {
??????? nx = x + dx[i];
??????? ny = dy[i] + y;
??????? if(!judge(nx,ny))
??????????? continue;
??????? if(map[nx][ny] == '.')
??????? {
??????????? count++;
??????????? dfs(nx,ny);
??????? }
??? }
}
int main()
{
??? //freopen("test.in", "r", stdin);
??? while(cin>>c>>r && r&&c)
??? {
??????? count = 1;
??????? int x0,y0;
??????? for(int i = 0; i < r; i++ )
??????? {
??????????? for(int j = 0 ; j < c; j++)
??????????? {
??????????????? cin>>map[i][j];
??????????????? if(map[i][j] == '@')
??????????????? {
??????????????????? x0 = i;
??????????????????? y0 = j;
??????????????? }
??????????? }
??????? }
??????? dfs(x0,y0);
??????? cout<<count<<endl;
??? }
??? return 0;
}

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2.bfs:

#include <iostream>
#include <queue>
using namespace std;
structnode { int r; int l;};
int m, n, sr, sl;
int dir[2][4] = {{-1, 1, 0, 0}, {0, 0, -1, 1}};
int visited[20][20];
int BFS();
int main()
{ int i, j; char str[21]; while(cin >> m >> n){	 if(m == 0 || n == 0){	break;	}	for(i = 0; i < n; i++){	 cin >> str;for(j = 0; j < m; j++) {	if(str[j] == '@'){	sr = i;	sl = j;	visited[i][j] = 1;	}	else if(str[j] == '.') {visited[i][j] = 0;	} else {	visited[i][j] = 1;}	} }int count = BFS();	 cout << count << endl;} return 0;}int BFS(){ int i, count; queue<node>Q; nodeN, temp; N.r = sr; N.l = sl;count = 1;Q.push(N); while(!Q.empty()){	 temp = Q.front();Q.pop();for(i = 0; i < 4; i++){	N = temp;	N.r += dir[0][i];	N.l += dir[1][i];if(N.r < 0 || N.r >= n ||	 N.l < 0 || N.l >= m) {	continue;	} else {	 if(!visited[N.r][N.l]){	count++;visited[N.r][N.l] = 1;Q.push(N);	}	}}} 
return count;
}

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