MEDIUM NC#138 Blind #46 Math & Geometry
73. Set Matrix Zeroes
📖 Problem
Given an m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place with O(1) extra space.
🧠 Visual Learning Aid
1 Model the input into the right structure
2 Choose the core technique and invariant
3 Execute step-by-step with a sample
4 Validate complexity and edge cases
JS/TS Refreshers
- •Array methods (`push`, `pop`, `shift`, `slice`)
- •Object/Map/Set usage patterns
- •Function parameter and return typing
Logical Thinking Concepts
- •Define invariants before coding
- •Check edge cases first (`[]`, single element, duplicates)
- •Estimate time/space before implementation
💡 Approach
- → Use first row and first column as markers
- → Track if first row/col needs to be zeroed separately
- → First pass: use first row/col to mark which rows/cols need zeroing
- → Second pass: set cells to 0 based on markers
- → Finally zero first row/col if needed
- → Time: O(m * n), Space: O(1)
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •Use first row and first column as markers
- •Track if first row/col needs to be zeroed separately
- •First pass: use first row/col to mark which rows/cols need zeroing
Common Pitfalls
- •Second pass: set cells to 0 based on markers
- •Finally zero first row/col if needed
- •Time: O(m * n), Space: O(1)
🧪 Test Cases
Test Case 1
Not run Input:
setZeroes(matrix1); Expected:
null Test Case 2
Not run Input:
setZeroes(matrix2); Expected:
null Test Case 3
Not run Input:
setZeroes(matrix: number[][]); Expected:
Computed from hidden reference 📝 Code Editor
📤 Output