Set Matrix Zeroes (In-place Marking) — Array/Matrix Manipulation Patterns

The Set Matrix Zeroes (In-place Marking) pattern applies when you need the Set Matrix Zeroes (In-place Marking) technique within the Array/Matrix Manipulation Patterns pattern. Its time complexity is O(m × n) and space complexity O(1). It is used in 3 problems on Thita, including Diagonal Traverse, Game of Life and Set Matrix Zeroes. Common variations are Product Except Self (Prefix/Suffix Products) and Merge Sorted Array (In-place from End).

Learn the in-place marking technique to set entire rows and columns to zero efficiently without extra space.

Set Matrix Zeroes (In-place Marking) is one of the 10 subpatterns of the Array/Matrix Manipulation Patterns pattern, which covers in-place operations, hashing, prefix sums, spiral traversal, and cyclic sort. The whole pattern is about 4 hours of study. This subpattern is a core technique: expect it to come up directly in interviews.

What Set Matrix Zeroes (In-place Marking) covers

Master array and matrix manipulation techniques including in-place rotation, spiral traversal, prefix/suffix products, and cyclic sort. Essential patterns for coding interviews at FAANG companies. Problems in this subpattern are usually searched for as set matrix zeroes, in-place marking, matrix zeroes, space optimization, leetcode 73.

How to practise Set Matrix Zeroes (In-place Marking) on Thita.ai

Read the theory for Set Matrix Zeroes (In-place Marking), then work the problems attached to it in the browser editor. Your solution runs against the problem's test cases, and the AI coach offers a hint about the technique you are missing rather than a finished solution. Progress is tracked per subpattern, so the Array/Matrix Manipulation Patterns tracker shows this one as covered once you have solved its problems.

Other subpatterns in Array/Matrix Manipulation Patterns

• Merge Sorted Array (In-place from End) — Learn the merge sorted array technique starting from the end. Essential for space-efficient array merging in coding interviews.
• Spiral Traversal — Master spiral traversal pattern for 2D matrices. Learn to traverse matrices in spiral order for interview problems.
• Hashing - Frequency Map / Counting — Master hash map frequency counting for array problems. Count occurrences, find duplicates, and solve majority element problems efficiently.
• Prefix Sum - Subarray Sum / Range Query — Master prefix sum technique for efficient subarray sum and range query problems. Solve subarray sum equals K and contiguous array problems.
• Product Except Self (Prefix/Suffix Products) — Master the prefix and suffix products technique to calculate product of array except self without division.
• Plus One (Handling Carry) — Learn to handle carry operations when adding one to a number represented as an array of digits.
• Array - Cyclic Sort — Master cyclic sort pattern to find missing, duplicate, or misplaced numbers in arrays with O(n) time and O(1) space.
• Hashing - Previously Seen / Existence Check — Use hash sets for O(1) existence checks. Track previously seen elements to detect duplicates, find pairs, and validate sequences.
• In-place Rotation — Learn in-place rotation techniques for arrays and matrices. Rotate without using extra space.

Related DSA patterns

• Sliding Window — Fixed-size, variable-size, and character frequency matching window techniques.
• Binary Search Patterns — Standard binary search, rotated arrays, first/last occurrence, and search on answer space.
• Linked List Manipulation Patterns — In-place reversal, merging sorted lists, reordering, and intersection detection.
• Stack Patterns — Parentheses matching, monotonic stack, histogram, and expression evaluation.

Where to go next

Set Matrix Zeroes (In-place Marking) is one lesson in a 16-pattern DSA course. If you are preparing end to end, work the interview-critical patterns first and use the pattern sheet as the checklist; if you are here for one technique, the Array/Matrix Manipulation Patterns guide is the shortest path back to the rest of it.

• The Array/Matrix Manipulation Patterns pattern guide
• All DSA patterns
• The DSA patterns sheet
• Coding practice