受最近关于SO的问题启发...

编写函数以以下格式打印二叉树：

   3
 /   \
1     5
 \   / \
  2 4   6

1. 输出应由一行节点组成，然后由一行/和\表示关系的字符组成，再由一行节点等。
2. 您可以假设所有节点都可以表示为单个字符。
3. 最低层的相邻节点应至少隔开一个空间，上方的节点应适当分开。
4. 有两个孩子的节点应精确地放置在其直接孩子的中间。
5. 亲子关系应该在父母和合适的孩子之间的中间位置（无论您选择哪种方式）。

输入：

输入将作为函数的参数提供。我不会指定树的确切结构，但是它必须可用作实际的二叉树。在我的程序中，没有“树以字符串的形式同时显示为预期的输出”。

您可以打印到输出流或返回包含您选择的输出的字符串。

最短代码的要点，但是与90％正常工作的短解决方案相比，我更喜欢完整工作的长期解决方案。

更新赏金：

为了奖励，我（优化程序）进行了一些小的更改：

• 输入可以来自STDIN，ARGV或函数参数。
• 输出必须在STD​​OUT上（或console.log对于JS）
• 您可以假设输入为数组形式，例如。[1,2,3]要么[1 2 3]

更新2-二进制树实际上应该是二进制搜索树。由于我最初没有提到这一点，因此我将允许用户将将普通数组转换为二进制搜索树数组作为单独的程序对待，而最终字节数仅用于程序将数组作为参数并打印出来像二叉树。

Fortran 77-1085个字符

      subroutine q(u,t)
      implicit integer(i-z)
      character*33 f,g
      dimension t(u)
      m=ceiling(log(real(u))/log(2.))
      v=2**(m+1)-1
      do l=1,m
         n=2**(l-1)
         k=2**(m-l+2)-3
         w=(3+k)*2**(l-1)-k
         p=1+(v-w)/2
         if(l.ne.1)then
            write(f,'(A,I3,A)')'(A',p,',$)'
            print f,' '
            write(f,'(A5,I3,A3)')'(A3,A',k,',$)'
            do j=2**(l-1),2**l-1
               if(t(j/2).lt.0.or.t(j).lt.0)then
                  print f,'   ',' '
               elseif(mod(j,2).eq.0)then
                  print f,'  /',' '
               else
                  print f,' \ ',' '
               endif
            enddo
            print*
         endif
         write(f,'(A,I3,A)')'(A',p,',$)'
         print f,' '
         write(f,'(A5,I3,A3)')'(I3,A',k,',$)'
         write(g,'(A2,I3,A3)')'(A',k+3,',$)'
         do j=2**(l-1),2**l-1
            if(t(j).ge.0)then
               print f,t(j),' '
            else 
               print g,' '
            endif
         enddo
         print*
      enddo
      end

树t以通常的方式在输入数组中表示，根在1处，root->左在2处，根->右在3处根->左->左在4处...

输出应适合多达5级深度的常规端子。

我在每对节点之间使用一个斜杠，一旦有四个或更多的级别，在顶部附近看起来就很傻了。我最多允许三个数字节点。

带有注释和启动支架的完整程序：

      program tree

      parameter (l=8)          ! How many nodes to support
      dimension i(l)

c     Initialize the array to all empty nodes
      do j=1,l
         i(j)=-1
      end do
c     Fill in some values
      i(1)=3
      i(2)=1
      i(3)=5
      i(5)=2
      i(6)=4
      i(7)=7
c      i(14)=6
c      i(15)=8
c     Call the printing routine
      call q(l,i)

      stop
      end

c     Print an ASCII representation of the tree
c
c     u the length of the array containing the tree
c     t an integer array representing the tree.
c
c     The array contains only non-negative values, and empty nodes are
c     represented in the array with -1.
c
c     The printed representation uses three characters for every node,
c     and places the (back) slash equally between the two node-centers.
      subroutine q(u,t)
      implicit integer(i-z)
      character*33 f,g
      dimension t(u)
      m=ceiling(log(real(u))/log(2.)) ! maximum depth of the tree
      v=2**(m+1)-1              ! width needed for printing the whole tree
                                ! Optimized from 3*2**m + 1*((2**m)-1) at
                                ! the bottom level
      do l=1,m
         n=2**(l-1)             ! number of nodes on this level
         k=2**(m-l+2)-3         ! internode spacing
         w=(3+k)*2**(l-1)-k     ! width needed for printing this row
                                ! Optimized from 3*2**l + k*((2**l)-1) at
                                ! the bottom level
         p=1+(v-w)/2            ! padding for this row
c     Print the connecting lines associated with the previous level
         if(l.ne.1)then         ! Write the connecting lines
            write(f,'(A,I3,A)')'(A',p,',$)'
            print f,' '
            write(f,'(A5,I3,A3)')'(A3,A',k,',$)'
            do j=2**(l-1),2**l-1
               if(t(j/2).lt.0.or.t(j).lt.0)then
                  print f,'   ',' '
               elseif(mod(j,2).eq.0)then
                  print f,'  /',' '
               else
                  print f,' \ ',' '
               endif
            enddo
            print*
         endif
c     Print the nodes on this level
         write(f,'(A,I3,A)')'(A',p,',$)'
         print f,' '
         write(f,'(A5,I3,A3)')'(I3,A',k,',$)'
         write(g,'(A2,I3,A3)')'(A',k+3,',$)'
         do j=2**(l-1),2**l-1
            if(t(j).ge.0)then
               print f,t(j),' '
            else 
               print g,' '
            endif
         enddo
         print*
      enddo
      end

输入等于示例的输出：

$ ./a.out 
         3             
     /      \      
     1       5     
      \    /  \  
       2   4   7 

CJam，100 99字节

q~_,2b,)2\#:Q1@{_2$<Q(S*:T*TQ2/:Q@ts[N+_0@{@1$' >{2$St2$_Q3*&2/^_4$>"\/"=t}*@)}/;U*o]o1:U$>\2*\}h];

输入必须是一个字符列表，没有任何ASCII控制字符。空节点用空格表示。它也必须是一个完全具有2 ⁿ -1个节点的理想二叉树。

例：

['6 '3 '7 '1 '4 '  '9 '0 '2 '  '5 '  '  '8 ' ]

或者简单地使用字符串：

"63714 902 5  8 "

输出：

                6              
            /       \          
        3               7      
      /   \               \    
    1       4               9  
   / \       \             /   
  0   2       5           8    

说明

q~                        " Read input. ";
_,2b,                     " Get tree height. ";
)2\#:Q                    " Get (displayed) tree width and save it in Q. ";
1@                        " Push X=1 and rotate the input to top. ";
{                         " Do: ";
    _2$<                  " Get first X characters from the input. ";
    Q(S*:T                " T = (Q-1) spaces. ";
    *                     " Separate the X characters by T. ";
    TQ2/:Q@t              " Put the string in the middle of T, and divide Q by 2. ";
    s                     " Concatenate everything into a string.
                            This is the line of node labels. ";
    [
        N+                " Append a newline. ";
        _                 " Duplicate. ";
        0@                " Push a 0 and rotate the original string to top. ";
        {                 " For each character: ";
            @             " Rotate the duplicate to top. ";
            1$' >         " Test if the current character is greater than a space. ";
            {             " If true: ";
                2$St      " Set the current character in the duplicate to space. ";
                2$        " Copy the current position I (the number initialized with 0). ";
                _Q3*&2/^  " Calculate I ^ ((I & (3*Q))>>1),
                            the position of the relationship character. ";
                _4$>      " Test if it is greater than the current position. ";
                "\/"=     " Select the relationship character. ";
                t         " Change the character in the duplicate. ";
            }*
            @)            " Increment the current position. ";
        }/
                          " The last two items are the line of relationship characters
                            and the tree width. ";
        ;                 " Discard the tree width. ";
        U*                " If it is the first line, empty the line of
                            relationship characters. ";
        o                 " Output. ";
    ]o                    " Output the line of node labels. ";
    1:U                   " Mark it not the first line. ";
    $>                    " Remove the first X characters from the input. ";
    \2*\                  " Multiply X by 2. ";
}h                        " ...while the input is not empty. ";
];                        " Discard everything in the stack. ";

转换脚本

[[0LL]W]
[q~{_a_:i={'0+}*}%La2*f+
_,,]z$
1$a+
{
    {
        1$1=1$1=>:T
        {
            ~@0=2 3$1=t
            @1@ta\+
        }*
        T
    }g
}*
0=1=a
{
    {
        (M\+:M;
        La[' LL]aer~
    }%
    _[' LL]a-
}g
];
M0+`-3<']+

它接受字符或一位数字。

例子（都是一样的）：

['6 '7 '9 '3 '1 '2 '8 '4 '0 '5]
[6 7 9 3 1 2 8 4 0 5]
"6793128405"

输出：

['6 '3 '7 '1 '4 ' '9 '0 '2 ' '5 ' ' '8 ' ]

这是直截了当的笛卡尔树结构。

Python 2，411字节

import math
def g(a,o,d,l,b):
 if l<0:
    return
 c=2*b+1
 k=2*l+1
 o[k]=' '*b
 n=d-l
 p=1 if n==0 else 3*2**n-1
 o[k-1]=p/2*' '
 i=0
 for v in a[2**l-1:2**l*2-1]:
    v=' ' if v==None else v
    o[k]+=v+' '*c
    m=' ' if v==' ' else '/' if i%2==0 else '\\'
    o[k-1]+=m+max(1,b)*' ' if i%2==0 else m+p*' '
    i+=1

 g(a,o,d,l-1,c)
def f(a):
 d=int(math.log(len(a),2))
 o=['']*(d*2+2)
 g(a,o,d,d,0)
 print '\n'.join(o[1:])

注意：第一个缩进级别是1个空格，第二个是一个制表符。

f用一个单字符字符串或的列表进行调用None，例如。f(['1',None,'3'])。列表不能为空。

这应遵守赏金规则。

转换器脚本：

将和转换为二进制树打印机使用的格式。例：

$ python conv.py [3,5,4,6,1,2]
['3', '1', '5', None, '2', '4', '6']

--

import sys

def insert(bt, i):
    if i < bt[0]:
        j = 0
    else:
        j = 1

    n = bt[1][j]
    if n == [None]:
        bt[1][j] = [i, [[None], [None]]]
    else:
        insert(bt[1][j], i)

def insert_empty(bt, i):
    if i == 0:
        return
    if bt == [None]:
        bt += [[[None], [None]]]

    insert_empty(bt[1][0], i - 1)
    insert_empty(bt[1][1], i - 1)

def get(l, level):
    if level == 0:
        if type(l) == list:
            return ([], l)
        else:
            return ([l], [])
    elif type(l) != list:
        return ([], [])

    res = []
    left = []

    for r, l in  [get(i, level - 1) for i in l]:
        res += r
        left += l

    return (res, left)

if __name__ == '__main__':
    l = eval(sys.argv[1])
    bt = [l[0], [[None], [None]]]
    map(lambda x: insert(bt, x), l[1:])

    depth = lambda l: 0 if type(l) != list else max(map(depth, l)) + 1
    d = (depth(bt) + 1) / 2

    insert_empty(bt, d - 1)

    flat = []
    left = bt
    i = 0
    while len(left) > 0:
        f, left = get(left, 1)
        flat += f

        i += 1

    for i in range(len(flat) - 1, -1, -1):
        if flat[i] == None:
            flat.pop()
        else:
            break

    flat = map(lambda x: None if x == None else str(x), flat)

    print flat

例子：

要运行这些文件，您应具有名为的主文件bt.py和名为的转换文件conv.py。

$ python conv.py [3,5,4,6,1,2] | python -c 'import bt; bt.f(input())'
   3
  / \
 1   5
  \ / \
  2 4 6
$ python conv.py [5,4,3,7,9] | python -c 'import bt; bt.f(input())'
   5
  / \
 4   7
/     \
3     9
$ python conv.py [1,2,3,4,5,6] | python -c 'import bt; bt.f(input())'
                               1
                                       \
                                               2
                                                   \
                                                       3
                                                         \
                                                           4
                                                            \
                                                             5
                                                              \
                                                              6
$ python conv.py [6,5,4,3,2,1] | python -c 'import bt; bt.f(input())'
                                   6
                       /
               5
           /
       4
     /
   3
  /
 2
/
1

APL，125个字符

{⍵{x←⍵[0;d←⌈2÷⍨1⌷⍴⍵]←↑⍺
2 1∇{x[2↓⍳↑⍴x;(⍳d)+d×⍺-1]←⍵(⍺⍺⍣t←0≠⍴⍵)2↓x[;⍳d]
x[1;d+(⌈d÷4)ׯ1*⍺]←' /\'[t×⍺]}¨⍺[2 1]
x}' '⍴⍨2(×,*)≡⍵}

例：

{⍵{x←⍵[0;d←⌈2÷⍨1⌷⍴⍵]←↑⍺
2 1∇{x[2↓⍳↑⍴x;(⍳d)+d×⍺-1]←⍵(⍺⍺⍣t←0≠⍴⍵)2↓x[;⍳d]
x[1;d+(⌈d÷4)ׯ1*⍺]←' /\'[t×⍺]}¨⍺[2 1]
x}' '⍴⍨2(×,*)≡⍵}('1' ('2' ('3' ('4' ()()) ('5' ()())) ('6' ()('7' ()())))('8' ()('9' ('0' ()())())))

在这里测试。

Ruby，265个字节

def p(t);h=Math.log(t.length,2).to_i;i=-1;j=[];0.upto(h){|d|s=2**(h-d)-1;c=2**d;if d>0;m=' '*(s+s/2)+'I'+' '*(s-s/2);1.upto(d){m+=' '+m.reverse};w=i;puts m.gsub(/I/){|o|t[w+=1]?(w%2==0?'\\':'/'):' '};end;puts (0...c).map{' '*s+(t[i += 1]or' ').to_s+' '*s}*' ';};end

@proudhaskeller版本，269个字节

def p(t);h=Math.log(t.length,2).to_i;i=-1;j=[];0.upto(h){|d|s=(z=2**(h-d))-1;c=2**d;if d>0;m=' '*(s+z/2)+'I'+' '*(s-z/2);1.upto(d){m+=' '+m.reverse};w=i;puts m.gsub(/I/){|o|t[w+=1]?(w%2==0?'\\':'/'):' '};end;puts (0...c).map{' '*s+(t[i += 1]or' ').to_s+' '*s}*' ';};end

讲解

详细版本：

def p(t)
  depth = Math.log(t.length, 2).floor
  i = -1
  j = []
  (0..depth).each do |d|
    s = 2 ** (depth-d)-1
    c = 2 ** d

    if d > 0
      m = ' '*(s+s/2) + '|' + ' '*(s-s/2)
      w = i
      1.upto(d) { m += ' ' + m.reverse }
      puts m.gsub(/\|/) { |o| t[w+=1] ? (w%2==0 ? '\\' : '/') : ' ' }
    end

    puts (0...c).map{' '*s+(t[i += 1]or' ').to_s+' '*s}*' '
  end
end

例

n = nil
p([
  1, 2, 3, 4, 5,
  n, 7, 8, 9, 0,
  1, n, n, 4, 5,
  6, 7, 8, 9, 0,
  1, 2, 3, n, n,
  n, n, 8, 9, n,
  n
])

给出：

               1               
          /         \          
       2               3       
    /     \               \    
   4       5               7   
 /   \   /   \           /   \ 
 8   9   0   1           4   5 
/ \ / \ / \ / \         / \    
6 7 8 9 0 1 2 3         8 9   

（我尚未编写转换脚本。）