POJ 2243 Knight Moves
http://poj.org/problem?id=2243
BFS模板题
1 #include <stdio.h> 2 #include <string.h> 3 #include <stdlib.h> 4 #include <queue> 5 using namespace std; 6 char pos_start[3],pos_end[3]; 7 bool visited[20][20]={false}; 8 int dis[20][20]={0}; 9 typedef struct Node { 10 int x,y; 11 }Node; 12 Node nodes[8]={{-1,-2},{-2,-1},{-2,1},{-1,2},{1,-2},{1,2},{2,-1},{2,1}}; 13 void init() 14 { 15 memset(visited,false,sizeof(visited)); 16 int i,j; 17 for(i=0;i<20;i++) 18 for(j=0;j<20;j++) 19 dis[i][j]=0; 20 } 21 bool check(int x,int y) 22 { 23 if(!(1<=x&&x<=8&&0<=y&&y<=7)) return false; 24 return true; 25 } 26 int bfs(int s_x,int s_y,int e_x,int e_y) 27 { 28 queue<int> Q; 29 Q.push(s_x); 30 Q.push(s_y); 31 dis[s_x][s_y]=0; 32 while(!Q.empty()) { 33 int x=Q.front(); 34 Q.pop(); 35 int y=Q.front(); 36 Q.pop(); 37 if(x==e_x&&y==e_y) return dis[x][y]; 38 visited[x][y]=true; 39 int i; 40 for(i=0;i<8;i++) { 41 if(check(x+nodes[i].x,y+nodes[i].y)&&!visited[x+nodes[i].x][y+nodes[i].y]) { 42 Q.push(x+nodes[i].x); 43 Q.push(y+nodes[i].y); 44 dis[x+nodes[i].x][y+nodes[i].y]=dis[x][y]+1; 45 } 46 } 47 } 48 } 49 50 int main() 51 { 52 while(scanf("%s%s",pos_start,pos_end)!=EOF) { 53 int start_x=pos_start[1]-'0'; 54 int start_y=pos_start[0]-'a'; 55 int end_x=pos_end[1]-'0'; 56 int end_y=pos_end[0]-'a'; 57 int moves=bfs(start_x,start_y,end_x,end_y); 58 init(); 59 printf("To get from %s to %s takes %d knight moves.\n",pos_start,pos_end,moves); 60 } 61 return 0; 62 }
