poj2243BFS

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
struct node
{
    int x;
    int y;
    int step;
}q,end,w;
int vis[10][10];
char x,y;
int a,b;
int u[][2]={-2,-1,-1,-2,1,-2,2,-1,2,1,1,2,-1,2,-2,1};
int sum,c,d;
queue<node>s;
void bfs(int x,int y)
{
    end.x=d;
    end.y=c;
    q.x=x;
    q.y=y;
    q.step=0;
    queue<node>s;
    while(!s.empty())s.pop();
    s.push(q);
    while(!s.empty())
    {
        q=s.front();
        s.pop();
        if(q.x==end.x&&q.y==end.y)
        {
            printf("To get from %c%d to %c%d takes %d knight moves.\n",a-1+‘a‘,b,c-1+‘a‘,d,q.step);
            return;
        }
        for(int i=0;i<8;i++)
        {
            w.x=q.x+u[i][0];
            w.y=q.y+u[i][1];
            w.step=q.step+1;
            if(w.x>0&&w.x<9&&w.y>0&&w.y<9&&vis[w.x][w.y]==0)
            {
                s.push(w);
                vis[w.x][w.y]=1;
            }
        }
    }
}
int main()
{
    while(cin>>x>>b>>y>>d)
    {
        memset(vis,0,sizeof(vis));
        a=x-‘a‘+1;
        c=y-‘a‘+1;
        bfs(b,a);
    }
}