Coding Interview

Coding Interview

Jason Yang · 31 Mar, 2026

Minimum Window Substring (LeetCode 76): the sliding-window O(n) approach with character counts to shrink to the smallest valid window, with a visual.

Coding Interview

Jason Yang · 31 Mar, 2026

Longest Substring Without Repeating Characters (LeetCode 3): the sliding-window O(n) approach, and why the int[128] version can jump the left pointer instead of stepping — with interactive visuals.

Coding Interview

Jason Yang · 31 Mar, 2026

Valid Palindrome (LeetCode 125): the two-pointer O(n) check that skips non-alphanumerics in place, why it beats building a cleaned string, and the edge cases.

Coding Interview

Jason Yang · 30 Mar, 2026

Longest Consecutive Sequence (LeetCode 128): the hash-set O(n) trick that only counts from sequence starts, with an interactive step-by-step visual.

Coding Interview

Jason Yang · 27 Mar, 2026

3Sum (LeetCode 15): sort then two-pointer for an O(n^2) solution, why sorting unlocks it, and the three places duplicate triplets sneak in — with an interactive visualization.

Coding Interview

Jason Yang · 27 Mar, 2026

Container With Most Water (LeetCode 11): the two-pointer O(n) approach, and the short proof for why moving the shorter line never skips a better answer — with an interactive visualization.

Coding Interview

Jason Yang · 27 Mar, 2026

The Two Pointers technique explained with clear examples: sorted arrays, sliding windows, and linked lists — a practical guide for coding interviews.

Coding Interview

Jason Yang · 03 Dec, 2025

Search in Rotated Sorted Array (LeetCode 33): a modified O(log n) binary search that finds which half is sorted, with an interactive step visual.

Coding Interview

Jason Yang · 03 Dec, 2025

Divide and Conquer is more than Merge Sort: the 3-step design paradigm, how it differs from plain recursion, and the interview patterns that use it.

Coding Interview

Jason Yang · 02 Dec, 2025

Binary Search runs in O(log n) because it halves the search space every step. Here's the intuition, the math proof, and how it compares to linear search.

Coding Interview

Jason Yang · 02 Dec, 2025

Find Minimum in Rotated Sorted Array (LeetCode 153): the O(log n) binary search that locates the rotation pivot, explained step by step with examples.

Coding Interview

Jason Yang · 01 Dec, 2025

Dynamic Programming demystified: at its core, DP is just Divide and Conquer plus memory. See the connection and it gets far easier to explain in interviews.

Coding Interview

Jason Yang · 01 Dec, 2025

Maximum Product Subarray (LeetCode 152): why you track max and min together to handle negatives and zeros, and the O(n) dynamic-programming solution.

Coding Interview

Jason Yang · 29 Nov, 2025

Maximum Subarray (LeetCode 53): Kadane's algorithm explained as one decision — extend or restart — plus the O(n) to O(1) space drop and a full worked trace.

Coding Interview

Jason Yang · 28 Nov, 2025

Product of Array Except Self (LeetCode 238): the prefix and suffix product trick that avoids division for an O(n) solution, with an interactive visual.

Coding Interview

Jason Yang · 28 Nov, 2025

Prefix Sum and Suffix Product explained: what these algorithm terms really mean, why they beat naive recomputation, and where they show up in problems.

Coding Interview

Jason Yang · 27 Nov, 2025

Contains Duplicate (LeetCode 217): compare the brute-force, sorting, and hash-set approaches — and why 'just use a hash set' isn't always the right reflex.

Coding Interview

Jason Yang · 27 Nov, 2025

One-pass and greedy algorithms: how a single scan and greedy choices process large data with minimal memory — the core ideas and when they're optimal.

Coding Interview

Jason Yang · 26 Nov, 2025

Best Time to Buy and Sell Stock (LeetCode 121): the single-pass O(n) solution that tracks the lowest price so far, with an interactive step-by-step visual.

Coding Interview

Jason Yang · 11 Nov, 2025

Two Sum (LeetCode 1) two ways: the brute-force O(n^2) scan vs the hash-map O(n) approach — with the intuition, edge cases, and the space-time trade-off.