POJ 3248 Catch That Cow

http://poj.org/problem?id=3278

二维BFS

 #include <iostream>
 #include <stdio.h>
 #include <string.h>
 #include <queue>
 #define READ() freopen("in.txt", "r", stdin);

 using namespace std;

 struct Loc
 {
     int x, step;
     Loc () {}
     Loc(int x, int step) : x(x), step(step) {}
 };

 int N, K;
 bool use[];
 bool OK(int x)
 {
     if (x <  || x >  ) return false;
     else return true;
 }
 int bfs()
 {
     queue<Loc> que;
     que.push(Loc(N, ));
     while (!que.empty())
     {
         Loc crt = que.front();
         que.pop();
         if(use[crt.x]) continue;
         use[crt.x] = true;
         int nx = crt.x - ;
         if (OK(nx) && !use[nx])
         {
             if (nx == K) return crt.step+;
             else que.push(Loc(nx, crt.step+));
         }
         nx = crt.x + ;
         if (OK(nx))
         {
             if (nx == K && !use[nx]) return crt.step+;
             else que.push(Loc(nx, crt.step+));
         }
         nx = *crt.x;
         if (OK(nx) && !use[nx])
         {
             if (nx == K) return crt.step+;
             else que.push(Loc(nx, crt.step+));
         }
     }
 }
 int main()
 {
     //READ()
     scanf("%d%d", &N, &K);
     if (N == K) //有N == K的坑点 严谨一点
     {
         cout <<  << endl;
         return ;
     }
     memset(use, , sizeof(use));
     int ans = bfs();
     cout << ans << endl;
     return ;
 }