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Problem solution · Python

Logical or of Two Binary Grids Represented as Quad Trees

Logical or of Two Binary Grids Represented as Quad Trees: a Python solution using direct simulation. Learn the idea, check the complexity, and read the full code, with credit to Kamyu LeetCode Solutions.

Technique
Direct simulation
Source
Kamyu LeetCode Solutions
Length
35 lines
Start with the idea.

Try the problem first. If you get stuck, read the approach below, then write your own solution. The full code is at the bottom.

Approach

Direct simulation

For Logical or of Two Binary Grids Represented as Quad Trees, the implementation follows the problem’s operations directly while maintaining only the state needed for the next decision.

  1. Translate each rule into one explicit state update.
  2. Maintain the invariant after every processed item.
  3. Return the accumulated state once all relevant input has been handled.

Code notes

  • 35 lines of Python from the credited upstream file logical-or-of-two-binary-grids-represented-as-quad-trees.py.
  • The implementation keeps its working state in language-native values and containers.
  • No explicit loop blocks detected.

Complexity

Count the number and nesting of passes over the input, then include the maintained containers in the memory estimate.

Check the problem constraints before deciding whether this complexity will pass.

Source

Code and credit

This code comes from Kamyu LeetCode Solutions by kamyu104 and is used under the MIT licence.

Open problem ↗Original source ↗
Full codeLogical or of Two Binary Grids Represented as Quad Trees · PythonPython
Use this to learn the idea, then write your own version.
# Time:  O(n)# Space: O(h) class Node(object):    def __init__(self, val, isLeaf, topLeft, topRight, bottomLeft, bottomRight):        self.val = val        self.isLeaf = isLeaf        self.topLeft = topLeft        self.topRight = topRight        self.bottomLeft = bottomLeft        self.bottomRight = bottomRight  class Solution(object):    def intersect(self, quadTree1, quadTree2):        """        :type quadTree1: Node        :type quadTree2: Node        :rtype: Node        """        if quadTree1.isLeaf:            return quadTree1 if quadTree1.val else quadTree2        elif quadTree2.isLeaf:            return quadTree2 if quadTree2.val else quadTree1        topLeftNode = self.intersect(quadTree1.topLeft, quadTree2.topLeft)        topRightNode = self.intersect(quadTree1.topRight, quadTree2.topRight)        bottomLeftNode = self.intersect(quadTree1.bottomLeft, quadTree2.bottomLeft)        bottomRightNode = self.intersect(quadTree1.bottomRight, quadTree2.bottomRight)        if topLeftNode.isLeaf and topRightNode.isLeaf and \           bottomLeftNode.isLeaf and bottomRightNode.isLeaf and \           topLeftNode.val == topRightNode.val == bottomLeftNode.val == bottomRightNode.val:            return Node(topLeftNode.val, True, None, None, None, None)        return Node(True, False, topLeftNode, topRightNode, bottomLeftNode, bottomRightNode)

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