Set Matrix Zeroes
Detailed guide and Python implementation for the 'Set Matrix Zeroes' problem.
1. Concept Overview
The 'Set Matrix Zeroes' problem is a key challenge in the Math & Geometry section.
This implementation focuses on easy-level logic in Python.
We prioritize technical accuracy and code readability in our provided solutions.
2. Real-World Applications
3. Visual Intuition
Visualizing the logic flow for Set Matrix Zeroes.
4. Prerequisites
5. Step-by-Step Thinking
1. Understand the problem
Read the problem statement for Set Matrix Zeroes carefully.
2. Formulate brute force
Draft a simple iterative solution.
3. Identify inefficiency
Look for redundant calculations.
4. Optimize search path
Use hashing or sorting to speed up the process.
5. Final Implementation
Clean up the code for production standards.
Problem Statement
Given an m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's.
You must do it in place.
Implement a function setZeroes(matrix: list) -> list that modifies the matrix in place and returns it.
- •m == matrix.length
- •n == matrix[0].length
- •1 <= m, n <= 200
- •-2^31 <= matrix[i][j] <= 2^31 - 1
Examples
[[1,1,1],[1,0,1],[1,1,1]]
[[1,0,1],[0,0,0],[1,0,1]]
The element at position (1,1) is 0. So the entire row 1 and column 1 are set to 0.
[[0,1,2,0],[3,4,5,2],[1,3,1,5]]
[[0,0,0,0],[0,4,5,0],[0,3,1,0]]
Elements at (0,0) and (0,3) are 0. Row 0 becomes all zeros. Columns 0 and 3 become all zeros.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
Ready to Solve?
Open the problem in PyRun's browser-based Python editor. Your code runs fully offline — no server required.
Interview Insights & Variations
Complexity Analysis Breakdown
Why Time: Directly evaluates all possibilities.
Why Space: Uses standard local memory.
Why Time: Optimized paths reduce total operations.
Why Space: May trade memory for speed.
Optimized Solution Python Code
Optimized Solution Python Code
def set_zeroes_opt(matrix: list[list[int]]) -> None:
rows, cols = len(matrix), len(matrix[0])
row_zero = False
for r in range(rows):
for c in range(cols):
if matrix[r][c] == 0:
matrix[0][c] = 0
if r > 0:
matrix[r][0] = 0
else:
row_zero = True
for r in range(1, rows):
for c in range(1, cols):
if matrix[0][c] == 0 or matrix[r][0] == 0:
matrix[r][c] = 0
if matrix[0][0] == 0:
for r in range(rows):
matrix[r][0] = 0
if row_zero:
for c in range(cols):
matrix[0][c] = 0Brute Force Code (Spoiler Guarded)
Brute Force Code (Spoiler Guarded)
def set_zeroes_brute(matrix: list[list[int]]) -> None:
rows, cols = len(matrix), len(matrix[0])
row_zero = set()
col_zero = set()
for r in range(rows):
for c in range(cols):
if matrix[r][c] == 0:
row_zero.add(r)
col_zero.add(c)
for r in range(rows):
for c in range(cols):
if r in row_zero or c in col_zero:
matrix[r][c] = 0Algorithm Pattern Checklist
When dealing with Math & Geometry data patterns.
Core Prerequisites
Revision Key Notes
Common Mistakes & Pitfalls
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