uva-439 骑士的移动

bfs，用队列记录步数

#include <cstdio>#include <cstring>#include <vector>#include <queue>#include <iostream>using namespace std;#define DEBUGconst int maxn=1000+5,maxv=26;int a,b,c,d;bool visited[maxn][maxn];char s[maxn];int qx[maxn],qy[maxn],qcnt[maxn],f,t,cnt;int mv[8][2]={1,2,2,1,2,-1,1,-2,-1,-2,-2,-1,-2,1,-1,2};void bfs(){    qx[t]=a;    qcnt[t]=0;    qy[t++]=b;    while(t>f){        int u=qx[f];        int tcnt=qcnt[f];        int v=qy[f++];        if(u<0||u>7||v<0||v>7)continue;        if(visited[u][v])continue;        // printf("%d-%d-%d\n", u,v,tcnt);        visited[u][v]=1;        if(u==c&&v==d)printf("To get from %c%c to %c%c takes %d knight moves.\n",a+'a',b+'1',c+'a',d+'1',tcnt);        for(int i=0;i<8;i++){            qx[t]=u+mv[i][0];            qcnt[t]=tcnt+1;            qy[t++]=v+mv[i][1];        }    }}int main(){#ifdef DEBUG    freopen("in.txt", "r", stdin);    freopen("out.txt", "w", stdout);#endif    while(fgets(s,6,stdin)){        memset(visited,0,sizeof(visited));        memset(qx,0,sizeof(qx));        memset(qy,0,sizeof(qy));        memset(qcnt,0,sizeof(qcnt));        f=t=0;        a=s[0]-'a';        b=s[1]-'1';        c=s[3]-'a';        d=s[4]-'1';        // cout<<s<<endl;        // cout<<a<<b<<c<<d<<endl;        bfs();    }#ifdef DEBUG    fclose(stdin);    fclose(stdout);#endif    return 0;}