Practice Construct Quad Tree

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#427

LeetCode Problem

Construct Quad Tree

Array Divide and Conquer Tree Matrix

Problem Statement

Represent the n by n binary matrix grid with a quad tree and return its root. Each Node has boolean fields val and isLeaf, plus topLeft, topRight, bottomLeft, and bottomRight child pointers. If a region contains only one value, create a leaf whose val is that value (1 means true) and whose four children are null. Otherwise create a non-leaf, divide the region into four equal quadrants, and recursively build the corresponding children. A non-leaf may use either boolean value for val. The displayed output uses level-order serialization. Each node is [isLeaf, val], with booleans represented by 1 or 0; null marks an absent node.

Source: Construct Quad Tree on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input

grid = [[0,1],[1,0]]

Output

[[0,1],[1,0],[1,1],[1,1],[1,0]]

# Example 2

Input

grid = [[1,1,1,1,0,0,0,0],[1,1,1,1,0,0,0,0],[1,1,1,1,1,1,1,1],[1,1,1,1,1,1,1,1],[1,1,1,1,0,0,0,0],[1,1,1,1,0,0,0,0],[1,1,1,1,0,0,0,0],[1,1,1,1,0,0,0,0]]

Output

[[0,1],[1,1],[0,1],[1,1],[1,0],null,null,null,null,[1,0],[1,0],[1,1],[1,1]]

Constraints

n == grid.length == grid[i].length

n == 2^x where 0 <= x <= 6

Review your practice with PhantomCodeAI

After trying the problem yourself, use the app to discuss your approach, complexity, and edge cases.

Start Free