Question

我正在编写骑士游览问题，以便在n * n棋盘中找到骑士之旅。我已经做了2个答案，我认为这些答案是完全相同的。但是，在编译时，两个代码产生2个不同的结果。我想知道我的两个代码之间的区别。

`const max=10;
type square=array [-1..max+1,-1..max+1] of longint;
vector=array [1..max*max] of longint;
var n:longint;
x:array [1..8] of longint=(-2,-2,-1,-1,+1,+1,+2,+2);
y:array [1..8] of longint=(-1,+1,-2,+2,-2,+2,-1,+1);
c,r:square;
a,b:vector;
checking:boolean;
 procedure input;
  begin
  readln(n);
  end;
 procedure backTrack(i,u,v:longint);
 var j:longint;
  begin
  if (i>n*n) then
   begin
   checking:=true;
   exit;
   end;
  for j:=1 to 8 do
   begin
   if checking then exit;
   inc(u,x[j]);
   inc(v,y[j]);
   if (u>0) and (u<=n) and (v>0) and (v<=n) and (i<=n*n) and (c[u,v]=0) then
    begin
    c[u,v]:=1;
    r[u,v]:=i;
    backTrack(i+1,u,v);
    c[u,v]:=0;
    end;
   dec(u,x[j]);
   dec(v,y[j]);
   end;
  end;
 procedure solve;
  begin
  fillchar(c,sizeof(c),0);
  c[1,1]:=1;
  r[1,1]:=1;
  checking:=false;
  backTrack(2,1,1);
  end;
 procedure output;
 var j,i:longint;
  begin
  for j:=1 to n do
   begin
   for i:=1 to n do write(r[i,j],' ');
   writeln;
   end;
  readln;
  end;
begin
input;
solve;
output;
end.`

我的第二个代码：{{3}}

`const max=10;
type square=array [-1..max+1,-1..max+1] of longint;  
vector=array [1..max*max] of longint;
var n:longint;
x:array [1..8] of longint=(-2,-2,-1,-1,+1,+1,+2,+2);
y:array [1..8] of longint=(-1,+1,-2,+2,-2,+2,-1,+1);
c,r:square;
a,b:vector;
checking:boolean;
 procedure input;
  begin
  readln(n);
  end;
 procedure backTrack(i,u,v:longint);
 var j:longint;
  begin
  if (i>n*n) then
   begin
   checking:=true;
   exit;
  end;
  r[u,v]:=i;
  for j:=1 to 8 do
   begin
   if checking then exit;
   inc(u,x[j]);
   inc(v,y[j]);
   if (u>0) and (u<=n) and (v>0) and (v<=n) and (i<=n*n) and (c[u,v]=0) then
    begin
    c[u,v]:=1;
    backTrack(i+1,u,v);
    c[u,v]:=0;
    end;
   dec(u,x[j]);
   dec(v,y[j]);
   end;
  end;
 procedure solve;
  begin
  fillchar(c,sizeof(c),0);
  c[1,1]:=1;
  r[1,1]:=1;
  checking:=false;
  backTrack(1,1,1);
  end;
 procedure output;
 var j,i:longint;
  begin
  for j:=1 to n do
   begin
   for i:=1 to n do write(r[i,j],' ');
   writeln;
   end;
  end;
begin
input;
solve;
output;
end.`

事先，非常感谢你。

Answer 1

var center = Math.floor(myArray.length / 2; var parity = function(p){ return (p%2)*2-1; //if the number is even, returns -1 otherwise 1 } //adds to cetner location half on index, signed with its parity, so we get an alternating effect each time index grows bigger //for 0,1,2,3,4,5,6... will return 0,1,-1,2,-2,3,-3... var step = function(index){ return (Math.floor((index+1)/2))*parity(index); } for (var i=0;i<size;i++){ for (var j=0;j<size;j++){ a[center-step(i)][center-step(j)]; } }出现在r[u,v]:=i;之前的第二个代码中，但不出现在第一个代码中。

有differencing tools可用于分辨两个文本文件的不同之处。熟悉这些工具是个好主意。

奇怪的结果与预测不同（奈特的巡演）

1 个答案: