1 #include <bits/stdc++.h> 2 using namespace std; 3 struct Node 4 { 5 int r,c; 6 Node(int a,int b) : r(a),c(b) {} 7 Node() {} 8 }; 9 const int dr[] = {-2,-2,-1,-1,1,1,2,2}; 10 const int dc[] = {-1,1,-2,2,-2,2,-1,1}; 11 12 int r1,c1,r2,c2; 13 string in1,in2; 14 void read() 15 { 16 r1 = 8-(in1[1]-'0');c1 = in1[0]-'a'; 17 cin >> in2;r2 = 8-(in2[1]-'0');c2 = in2[0]-'a'; 18 } 19 20 int d[9][9]; 21 bool limit(Node u) 22 { 23 return u.r>=0&&u.r<=7&&u.c>=0&&u.c<=7; 24 } 25 int solve() 26 { 27 memset(d,-1,sizeof(d)); 28 queue<Node> q; 29 q.push(Node(r1,c1)); 30 d[r1][c1] = 0; 31 while(!q.empty()) 32 { 33 Node u = q.front(); 34 q.pop(); 35 if(u.r==r2&&u.c==c2) return d[r2][c2]; 36 for(int i = 0; i < 8; i ++) 37 { 38 Node v = u; 39 v.r += dr[i]; 40 v.c += dc[i]; 41 if(limit(v)&&d[v.r][v.c]<0) 42 { 43 d[v.r][v.c] = d[u.r][u.c] + 1; 44 q.push(v); 45 } 46 } 47 } 48 } 49 50 void print(int rnt) 51 { 52 cout << "To get from " <<in1<< " to " <<in2<< " takes " <<rnt<< " knight moves." << endl; 53 } 54 int main() 55 { 56 while(cin >> in1) 57 { 58 read(); 59 int rnt = solve(); 60 print(rnt); 61 } 62 return 0; 63 }