poj1979

简单题

View Code

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

#define maxn 25

struct XPoint
{
int x, y;
} a;

bool map[maxn][maxn], vis[maxn][maxn];
int n, m, ans;
int dir[4][2] =
{
{ 0, 1 },
{ 0, -1 },
{ 1, 0 },
{ -1, 0 } };

void input()
{
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
char ch;
scanf("%c", &ch);
if (ch == '#')
map[i][j] = false;
else
map[i][j] = true;
if (ch == '@')
{
a.x = i;
a.y = j;
}
}
getchar();
}
}

bool ok(XPoint &a)
{
if (a.x < 0 || a.y < 0 || a.x >= n || a.y >= m)
return false;
return !vis[a.x][a.y] && map[a.x][a.y];
}

void bfs()
{
memset(vis, 0, sizeof(vis));
queue<XPoint> q;
q.push(a);
vis[a.x][a.y] = true;
ans = 0;
while (!q.empty())
{
XPoint a = q.front();
q.pop();
ans++;
XPoint b;
for (int i = 0; i < 4; i++)
{
b.x = a.x + dir[i][0];
b.y = a.y + dir[i][1];
if (ok(b))
{
q.push(b);
vis[b.x][b.y] = true;
}
}
}
}

int main()
{
//freopen("t.txt", "r", stdin);
while (scanf("%d%d", &m, &n), m | n)
{
getchar();
input();
bfs();
printf("%d\n", ans);
}
return 0;
}

转载于:https://www.cnblogs.com/rainydays/archive/2011/06/08/2075439.html