poj2386

简单题

bfs

View Code

#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <queue>

using namespace std;



#define maxn 105



struct Point

{

    int x, y;

    Point()

    {}

    Point(int xx, int yy):x(xx), y(yy)

    {}

};



int n, m;

bool grid[maxn][maxn];

bool vis[maxn][maxn];

int dir[8][2] = {{1, 0}, {1, 1}, {1, -1}, {0, 1}, {0, -1}, {-1, -1}, {-1, 0}, {-1, 1}};

char st[maxn];



void input()

{

    memset(grid, 0, sizeof(grid));

    for (int i = 1; i <= n; i++)

    {

        scanf("%s", st);

        for (int j = 1; j <= m; j++)

        {

            grid[i][j] = (st[j - 1] == 'W');

        }

    }

}



bool ok(Point a)

{

    if (a.x > n || a.x < 1 || a.y > m || a.y < 1)

        return false;

    if (vis[a.x][a.y])

        return false;

    return grid[a.x][a.y];

}



void bfs(int sx, int sy)

{

    queue<Point> q;

    q.push(Point(sx, sy));

    vis[sx][sy] = true;

    while (!q.empty())

    {

        Point u = q.front();

        q.pop();

        for (int i = 0; i < 8; i++)

        {

            Point v;

            v.x = u.x + dir[i][0];

            v.y = u.y + dir[i][1];

            if (ok(v))

            {

                vis[v.x][v.y] = true;

                q.push(v);

            }

        }

    }    

}



int main()

{

//    freopen("t.txt", "r", stdin);

    while (scanf("%d%d", &n, &m) != EOF)

    {

        input();

        memset(vis, 0, sizeof(vis));

        int ans = 0;

        for (int i = 1; i <= n; i++)

            for (int j = 1; j <= m; j++)

                if (grid[i][j] && !vis[i][j])

                {

                    bfs(i, j);

                    ans++;

                }

        printf("%d\n", ans);

    }

    return 0;

}