> # include <iostream>
> # include <string.h>
> # include <queue>
> # define maxn 305
> using namespace std;
> 
> typedef struct node
> {
>     int x,y,step;
> };
> 
> int mark[maxn][maxn];
> int n;
> node s,e;
> int dr[][2]={{1,2},{2,1},{2,-1},{1,-2},{-1,2},{-2,1},{-2,-1},{-1,-2}};
> int bfs()
> {
>     queue<node>q;
>     node t;
>     int i;
>     if (s.x==e.x &&s.y==e.y)return 0;
>     q.push(s);
>     memset(mark,0,sizeof(mark));
>     mark[s.x][s.y]=1;
>     while (!q.empty())
>     {
>         s=q.front();
>         q.pop();
>         for (i=0;i<=7;i++)
>         {
>             t.x=s.x+dr[i][0];
>             t.y=s.y+dr[i][1];
>             if (t.x<0 ||t.x>=n ||t.y<0 ||t.y>=n)continue;
>             if (mark[t.x][t.y]==1)continue;
>             if (t.x==e.x && t.y==e.y)return t.step+1;
>             t.step=s.step+1;
>             q.push(t);
>             mark[t.x][t.y]=1;
>         }
> 
>     }
>     return -1;
> }
> 
> int main()
> {
>     int cas,dis;
>     cin>>cas;
>     while (cas--)
>     {
>         cin>>s.x>>s.y;
>         cin>>e.x>>e.y;
>         s.step=0;
>         dis=bfs();
>         cout<<dis<<endl;
>     }
>     return 0;
> }
> STL 的哪里有问题啊，感觉和下面的一模一样啊
> 
> # include <iostream>
> # include <string.h>
> # define maxn 305
> using namespace std;
> 
> typedef struct node
> {
>     int x,y,step;
> };
> 
> int dr[][2]={{1,2},{2,1},{2,-1},{1,-2},{-1,2},{-2,1},{-2,-1},{-1,-2}};
> node s,e;
> int mark[maxn][maxn],n;
> node queue[maxn*maxn];
> int bfs()
> {
>     int front,rear,i;
>     node t;
>     front=rear=0;
>     queue[rear++]=s;
>     memset(mark,0,sizeof(mark));
>     while (front<rear)
>     {
>         s=queue[front++];
>         if (s.x==e.x && s.y==e.y)return s.step;
>         for (i=0;i<=7;i++)
>         {
>             t.x=s.x+dr[i][0];
>             t.y=s.y+dr[i][1];
>             if (t.x<0 || t.x>=n || t.y<0 || t.y>=n )continue;
>             if (mark[t.x][t.y]==1)continue;
>             t.step=s.step+1;
>             queue[rear++]=t;
>             mark[t.x][t.y]=1;
>         }
>     }
>     return -1;
> }
> int main()
> {
>     int cas,dis;
>     cin>>cas;
>     while (cas--)
>     {
>         cin>>n;
>         cin>>s.x>>s.y;
>         cin>>e.x>>e.y;
>         s.step=0;
>         dis=bfs();
>         cout<<dis<<endl;
>     }
>     return 0;
> }
> 
> 
你看好你return的是什么。。