Joj2410: The knight problem

#include<iostream>   #include<cstdio>   #include<queue>   using namespace std;  typedef struct Point  {      int x, y;  }POINT;  queue <POINT> me;  POINT Begin , End;  bool visited[9][9];  bool flag;  int ans;  int movei[8]= {2,-2,1,-1,2,-2,1,-1};  int movej[8]= {1,-1,2,-2,-1,1,-2,2};  void init()  {      int i, j;      for(i = 0; i < 9; i++)          for(j = 0; j < 9; j++)              visited[i][j] = false;  }  bool isok(POINT *p)  {      if(p->x == End.x && p->y == End.y)          return true;      else          return false;  }  bool isin(POINT *pt)  {      if(pt->x >= 1 && pt->x <= 8)          if(pt->y >= 1 && pt->y <= 8)              return true;      return false;  }  void change(char *str, POINT *pt)  {      pt->x = str[0] - 'a' +1;      pt->y =str[1] - '0';  }  void bfs()  {      int i, q, casenum;      POINT pt, tp;      casenum = 1;      while(!me.empty())      {          ans++;          q = 0;          while(casenum--)          {              pt = me.front();              me.pop();              for( i = 0; i < 8; i++)              {                  tp.x = pt.x + movei[i];                  tp.y = pt.y + movej[i];                  if(isin(&tp))                  {                      if(visited[tp.x][tp.y])                          continue;                      else                      {                          if(isok(&tp))                          {                              flag = true;                              return;                          }                          else                          {                              visited[tp.x][tp.y] = true;                              me.push(tp);                              q++;                          }                      }                  }              }          }          casenum = q;      }      if(me.empty())          flag = false;      return ;  }  int main()  {      int n, i, casenum;      POINT tp;      char str[10];      casenum = 1;      while(true)      {          while(!me.empty())          me.pop();          flag = true;          ans = 0;          init();          scanf("%d", &n);          if(-1 == n)              break;          for(i = 0; i < n; i++)          {              scanf("%s", str);              change(str, &tp);              visited[tp.x][tp.y] = true;          }          scanf("%s", str);          change(str, &Begin);          scanf("%s", str);          change(str, &End);          me.push(Begin);          visited[Begin.x][Begin.y] = true;          if(isok(&Begin))              printf("Board %d: %d moves\n", casenum, ans);          bfs();          if(flag)              printf("Board %d: %d moves\n", casenum, ans);          else              printf("Board %d: not reachable\n", casenum);          casenum++;      }      return 0;  }