#include<cstdio> #include<queue> #include<cstring> using namespace std; //bfs水题 struct Node { int x; int y; int steps; Node(int a,int b,int c):x(a),y(b),steps(c) {} }; bool vis[10][10]; queue<Node>q; int dis[8][2] = {{1,2},{1,-2},{2,1},{2,-1},{-1,-2},{-1,2},{-2,-1},{-2,1}}; int newx,newy; int bfs(int sx,int sy,int ex,int ey) { if(sx==ex&&sy==ey) return 0; memset(vis,0,sizeof(vis)); while(!q.empty()) q.pop(); q.push(Node(sx,sy,0)); vis[sx][sy] = 1; while(!q.empty()) { Node now = q.front(); q.pop(); if(now.x==ex&&now.y==ey) return now.steps; for(int i = 0; i<8; ++i) { newx = now.x + dis[i][0]; newy = now.y + dis[i][1]; if(newx<8&&newx>=0&&newy<8&&newy>=0&&vis[newx][newy]==0) { if(newx==ex&&newy==ey) return now.steps+1; q.push(Node(newx,newy,now.steps+1)); vis[newx][newy] = 1; } } } return 0; } int main() { char s1[5],s2[5]; int x1,y1,x2,y2; while(~scanf("%s%s",s1,s2)) { x1 = s1[0]-'a'; y1 = s1[1]-'1'; x2 = s2[0]-'a'; y2 = s2[1]-'1'; printf("To get from %s to %s takes %d knight moves.\n",s1,s2,bfs(x1,y1,x2,y2)); } return 0; }