Package g0601_0700.s0655_print_binary_tree

Class Solution

  • public class Solution
extends Object
    655 - Print Binary Tree.

    Medium

    Given the root of a binary tree, construct a 0-indexed m x n string matrix res that represents a formatted layout of the tree. The formatted layout matrix should be constructed using the following rules:

    • The height of the tree is height and the number of rows m should be equal to height + 1.
    • The number of columns n should be equal to 2height+1 - 1.
    • Place the root node in the middle of the top row (more formally, at location res[0][(n-1)/2]).
    • For each node that has been placed in the matrix at position res[r][c], place its left child at res[r+1][c-2<sup>height-r-1</sup>] and its right child at res[r+1][c+2<sup>height-r-1</sup>].
    • Continue this process until all the nodes in the tree have been placed.
    • Any empty cells should contain the empty string "".

    Return the constructed matrix res.

    Example 1:

    Input: root = [1,2]

    Output: [[““,“1”,””], [“2”,““,””]]

    Example 2:

    Input: root = [1,2,3,null,4]

    Output: [[““,””,““,“1”,””,““,””], [““,“2”,””,““,””,“3”,""], [““,””,“4”,““,””,““,””]]

    Constraints:

    • The number of nodes in the tree is in the range [1, 210].
    • -99 <= Node.val <= 99
    • The depth of the tree will be in the range [1, 10].