洛谷 P1443 马的遍历

洛谷 P1443 马的遍历

---

题目

题目描述

有一个n*m的棋盘(1

题目

---

题解

BFS+手动左对齐(Pascal没有左对齐)

---

代码（Pascal）

const flag:array[1..8,0..1]of longint=((2,1),(1,2),(-1,2),(2,-1),(-2,-1),(-1,-2),(-2,1),(1,-2));var n,m,head,tail:longint;    q:array[0..160005]of record                           x,y:longint;                          end;    map:array[0..405,0..405]of longint;    vis:array[0..405,0..405]of boolean; procedure init;  begin    readln(n,m,q[1].x,q[1].y);   end; function check(x,y:longint):boolean;  begin    if (x<1)or(y<1)or(x>n)or(y>m) then exit(false);    if vis[x,y]=true then exit(false);    exit(true);   end; procedure find(x,y:longint);  begin    inc(tail);vis[x,y]:=true;    q[tail].x:=x;q[tail].y:=y;    map[x,y]:=map[q[head].x,q[head].y]+1;   end; procedure print(x:longint);  var i,t,y:longint;   begin     t:=0;y:=x;     if x<0 then begin                   x:=abs(x);                   inc(t);                  end;     if (x<=9) then inc(t) else     if (x<=99) then t:=t+2 else     if (x<=999) then t:=t+3 else     if (x<=9999) then t:=t+4;     write(y);     for i:=1 to 5-t do      write(' ');    end; procedure main;  var i,j,x,y:longint;   begin     fillchar(vis,sizeof(vis),0);     head:=0;tail:=1;     for i:=1 to n do      for j:=1 to m do       map[i,j]:=-1;     map[q[1].x,q[1].y]:=0;     vis[q[1].x,q[1].y]:=true;     while head<tail do      begin        inc(head);        x:=q[head].x;y:=q[head].y;        for i:=1 to 8 do         if check(x+flag[i,0],y+flag[i,1]) then find(x+flag[i,0],y+flag[i,1]);       end;     for i:=1 to n do      begin        for j:=1 to m do print(map[i,j]);        writeln;       end;     end; begin   init;   main;  end.