poj 2243 Knight Moves bfs

水题，裸的bfs，基本没有要注意的

/*author:jxylang:C/C++university:China,Xidian University**If you need to reprint,please indicate the source***/#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <queue>#define INF 1E9using namespace std;const int dir[8][2]={-2,-1,-2,1,-1,-2,-1,2,1,-2,1,2,2,1,2,-1};int vis[9][9];struct node{    int x,y;};queue<node> q;char aim[3],stt[3];node st,am,now,temp;int i;int main(){    while(~scanf("%s%s",stt,aim))    {        memset(vis,0,sizeof(vis));        while(!q.empty())q.pop();        st.x=stt[0]-'a';st.y=stt[1]-'1';        am.x=aim[0]-'a';am.y=aim[1]-'1';        vis[st.x][st.y]=1;        q.push(st);        while(!q.empty()&&!vis[am.x][am.y])        {            now=q.front();q.pop();            for(i=0;i<8;i++)            {                temp.x=now.x+dir[i][0];                temp.y=now.y+dir[i][1];                if(temp.x<0||temp.x>7||temp.y<0||temp.y>7||vis[temp.x][temp.y])continue;                vis[temp.x][temp.y]=vis[now.x][now.y]+1;                q.push(temp);            }        }        printf("To get from %s to %s takes %d knight moves.\n",stt,aim,vis[am.x][am.y]-1);    }}