poj2386（BFS与DFS）

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这个题就是求联通块

bfs代码

#include <cstdio>#include <iostream>#include <cstring>#include <algorithm>#include <queue>using namespace std;char s[233][233];int n,m,ans = 0;bool vis[233][233];int dx[9]={0,1,0,-1,1,-1,1,-1};int dy[9]={1,0,-1,0,1,-1,-1,1};struct point{    int x,y;};queue <point> q;void bfs(int x,int y){    q.push((point){x,y});    while(!q.empty())    {        point p = q.front();        q.pop();        for(int i = 0; i < 8; i ++)        {            int nx = dx[i]+ p.x;            int ny = dy[i]+ p.y;            if(s[nx][ny] == 'W' && !vis[nx][ny] && nx <= n && nx > 0 && ny <= m&&ny > 0)            {                q.push((point){nx,ny});                vis[nx][ny] = 1;            }        }    }}int main(){    scanf("%d%d",&n,&m);    for(int i = 1; i <= n; i ++)    for(int j = 1; j <= m; j ++)    cin >>s[i][j];    for(int i = 1; i <= n; i ++)    for(int j = 1; j <= m; j ++)    {        if(s[i][j] == 'W'&&!vis[i][j])        {            ans ++;            bfs(i,j);        }    }    printf("%d",ans);    return 0;}

dfs代码

#include <cstdio>#include <iostream>#include <cstring>#include <queue>using namespace std;char s[233][233];int n,m,ans = 0;bool vis[233][233];int dx[9] = {0,1,0,-1,1,-1,-1,1};int dy[9] = {1,0,-1,0,1,-1,1,-1};void dfs(int x,int y){    vis[x][y] = 1;    for(int i = 0; i < 8; i ++)    {        int nx = dx[i]+x;        int ny = dy[i]+y;        if(s[nx][ny]=='W' && !vis[nx][ny] && nx >0 &&nx <= n&& ny>0 && ny <=m)        {            vis[nx][ny] = 1;            dfs(nx,ny);        }    }}int main(){    scanf("%d%d",&n,&m);    for(int i = 1; i <= n; i ++)    for(int j = 1; j <= m; j ++)    cin >> s[i][j];    for(int i = 1 ;i <= n; i ++)    for(int j = 1; j <= m; j ++)    {        if(s[i][j] == 'W' && !vis[i][j])        {            ans ++;            dfs(i,j);        }    }    printf("%d" ,ans);    return 0;}

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