What is the Set Matrix Zeroes pattern?

The Set Matrix Zeroes is a common coding interview pattern in Matrices problems. It provides a structured approach to solving related algorithm challenges efficiently.

When should I use Set Matrix Zeroes?

Use the Set Matrix Zeroes pattern when you encounter problems matching its characteristics. Check the "When to Use" and "Clues" sections in the lesson for specific indicators.

Is Set Matrix Zeroes asked in FAANG interviews?

Yes, Set Matrix Zeroes is an essential pattern commonly tested in FAANG and top tech company technical interviews.

Matrices

Medium

Set Matrix Zeroes

If an element is 0, set its entire row and column to 0.

10 min read

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Problem Understanding

Given an m x n integer matrix, if an element is 0, set its entire row and column to 0. You must do it in-place.

Strategy (O(1) Space)

We can use the first row and first column as markers.

Check if first row/col originally have zeros. Store in flags.
Iterate through the rest of the matrix. If matrix[i][j] == 0, mark matrix[i][0] and matrix[0][j] as 0.
Iterate again to set zeros based on markers.
Handle first row/col separately using flags.

Use matrix[i][0] to store row status.
Use matrix[0][j] to store col status.

Interactive Visualization

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