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| 1 | +# construct quad tree | leetcode 427 | https://leetcode.com/problems/construct-quad-tree/ |
| 2 | +# recursively call each quad of the grid and check if each quad is uniform or not |
| 3 | + |
| 4 | +# Definition for a QuadTree node. |
| 5 | +class Node: |
| 6 | + def __init__(self, val, isLeaf, topLeft, topRight, bottomLeft, bottomRight): |
| 7 | + self.val = val |
| 8 | + self.isLeaf = isLeaf |
| 9 | + self.topLeft = topLeft |
| 10 | + self.topRight = topRight |
| 11 | + self.bottomLeft = bottomLeft |
| 12 | + self.bottomRight = bottomRight |
| 13 | + |
| 14 | + |
| 15 | +class Solution: |
| 16 | + def construct(self, grid: list[list[int]]) -> Node: |
| 17 | + def checkThisQuad(row, col, n) -> bool: |
| 18 | + for i in range(row, row + n): |
| 19 | + for j in range(col, col + n): |
| 20 | + if grid[i][j] != grid[row][col]: |
| 21 | + return False |
| 22 | + return True |
| 23 | + |
| 24 | + def quadTree(row, col, n): |
| 25 | + if checkThisQuad(row, col, n): |
| 26 | + return Node(grid[row][col], 1, None, None, None, None) |
| 27 | + |
| 28 | + |
| 29 | + return Node(grid[row][col], 0, |
| 30 | + quadTree(row, col, n//2), |
| 31 | + quadTree(row, col + n//2, n//2), |
| 32 | + quadTree(row + n//2, col, n//2), |
| 33 | + quadTree(row + n//2, col + n//2, n//2) |
| 34 | + ) |
| 35 | + |
| 36 | + return quadTree(0, 0, len(grid)) |
| 37 | + |
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