双向广搜

#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<vector>
#include<map>
#include<stack>
#include<queue>
#include<set>
#define maxn 305
#define INF 0x3f3f3f3f
#define MOD 1000000007
#define LL long long
#define e 2.71828182
using namespace std;
int n;
int nextz[8][2]={2,1,1,2,2,-1,1,-2,-2,1,-2,-1,-1,2,-1,-2};
int book[maxn][maxn];
int sx,sy,ex,ey;
struct node
{
   int x,y;
};
int step[maxn][maxn];
void bfs()//双向广搜
{
   memset(book,0,sizeof(book));
   memset(step,0,sizeof(step));
   queue<node>q;
   node h,h1,h2,t;
   h1.x=sx;h1.y=sy;
   h2.x=ex;h2.y=ey;
   q.push(h1);book[sx][sy]=1;
   q.push(h2);book[ex][ey]=2;
   int tx,ty;
   int ans,flag;
   flag=0;
   while(!q.empty())
   {
      h=q.front();
      q.pop();
      for(int i=0;i<8;i++)
      {
         tx=h.x+nextz[i][0];
         ty=h.y+nextz[i][1];
         if(tx<0||ty<0||tx>=n||ty>=n)
            continue;
         if(book[tx][ty]&&book[h.x][h.y]&&book[tx][ty]!=book[h.x][h.y])
         {
            flag=1;
            ans=step[h.x][h.y]+step[tx][ty]+1;
            break;
         }
        if(!book[tx][ty])
        {
           t.x=tx;
           t.y=ty;
           q.push(t);
           step[tx][ty]=step[h.x][h.y]+1;
           book[tx][ty]=book[h.x][h.y];
        }
      }
      if(flag)
      {
         break;
      }
   }
   //cout << flag << endl;
   if(flag)
   {
      cout << ans << endl;
   }
}
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
       cin>>n;
       cin>>sx>>sy>>ex>>ey;
       if(sx==ex&&sy==ey)
       {
          cout << 0 << endl;
          continue;
       }
       bfs();
    }
    return 0;
}