马的遍历（BFS
https://www.luogu.org/problemnew/show/P1443
模板BFS......
1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4 #include<cstring> 5 #include<cmath> 6 #include<string> 7 #include<cmath> 8 #include<set> 9 #include<vector> 10 #include<stack> 11 #include<queue> 12 #include<map> 13 using namespace std; 14 #define ll long long 15 #define se second 16 #define fi first 17 const int INF= 0x3f3f3f3f; 18 const int N=1e5+5; 19 20 int n,m,a,b; 21 int dx[8]={2,2,1,1,-2,-2,-1,-1},dy[8]={1,-1,2,-2,1,-1,2,-2}; 22 int step[405][405]; 23 bool vis[405][405]; 24 25 struct note 26 { 27 int x,y; 28 int s; 29 }w,p; 30 31 queue<note>q; 32 33 void bfs(int ax,int ay) 34 { 35 w.x=ax; w.y=ay; w.s=0; 36 vis[w.x][w.y]=1; 37 step[w.x][w.y]=w.s; 38 39 q.push(w); 40 while( !q.empty()) 41 { 42 p=q.front(); 43 q.pop(); 44 for(int i=0;i<8;i++) 45 { 46 w.x=p.x+dx[i]; 47 w.y=p.y+dy[i]; 48 if(w.x<=n&&w.x>=1&&w.y<=m&&w.y>=1&&vis[w.x][w.y]==0) 49 { 50 vis[w.x][w.y]=1; 51 w.s=p.s+1; 52 step[w.x][w.y]=w.s; 53 q.push(w); 54 } 55 } 56 } 57 } 58 59 int main() 60 { 61 cin>>n>>m>>a>>b; 62 memset(step,-1,sizeof(step)); 63 bfs(a,b); 64 for(int i=1;i<=n;i++){ 65 for(int j=1;j<=m;j++) 66 printf("%-5d",step[i][j]); 67 cout<<endl; 68 } 69 }
