↓Skip to main content

LeetCode

LeetCode 503: Next Greater Element II (Monotonic Stack)
·2 mins
LeetCode Daily Medium Array Stack Monotonic-Stack Circular-Array
Monotonic stack on a circular array
LeetCode 496: Next Greater Element I (Monotonic Stack)
·2 mins
LeetCode Daily Easy Array Stack Monotonic-Stack Hash-Map Next-Greater-Element
Monotonic decreasing stack over nums2 to build next-greater map; answer queries for nums1.
LeetCode 3439: Reschedule Meetings for Maximum Free Time (Sliding Window)
·3 mins
LeetCode Daily Medium Array Sliding-Window Two-Pointers Intervals
Sliding window over meetings; track total duration in a k-sized window and compute free span between boundaries.
LeetCode 30: Substring with Concatenation of All Words (Brute Force → Counting → Sliding Window)
·3 mins
LeetCode Daily Hard String Sliding-Window Two-Pointers Hash-Map Brute-Force Frequency-Counting
Three approaches: brute force, counting optimization, and sliding window over word-length offsets.
LeetCode 209: Minimum Size Subarray Sum (Sliding Window)
·1 min
LeetCode Daily Medium Array Sliding-Window Two-Pointers Prefix-Sum Binary-Search
Sliding window with two pointers; minimize subarray length where sum ≥ target.
LeetCode 1695: Maximum Erasure Value (Sliding Window)
·1 min
LeetCode Daily Medium Array Sliding-Window Two-Pointers Hash-Set
Sliding window with a set and running sum; two pointers to keep the subarray unique.
LeetCode 1497: Check If Array Pairs Are Divisible by k (Remainder Pairing, Modulo)
·2 mins
LeetCode Daily Medium Array Hash-Map Complement Counting Math Modulo
Remainder pairing with a hash map; handle 0 and k/2 remainders carefully.
LeetCode 1071: Greatest Common Divisor of Strings
·2 mins
LeetCode Daily Easy String Gcd Math
LeetCode Problem Solving
LeetCode 2709: Greatest Common Divisor Traversal
·3 mins
LeetCode Hard Math Number-Theory Union-Find Sieve Gcd Array
LeetCode 2709 note: every pair of indices connects ⇔ one component; factor with SPF and union each number with its prime factors in Union-Find, treating 1 specially
LeetCode 2441: Largest Positive Integer That Exists With Its Negative
·2 mins
LeetCode Easy Hash-Map Two-Pointers Sorting
LeetCode 2441 note: keep positives and absolute values of negatives in separate sets and take the largest common value; absolute values alone mistake same-sign duplicates for pairs
LeetCode 904: Fruit Into Baskets
·3 mins
LeetCode Daily Medium Sliding-Window Variable-Window Two-Pointers Hash-Map
LeetCode Problem Solving - Variable Size Sliding Window with Hash Map
LeetCode 76: Minimum Window Substring
·3 mins
LeetCode Daily Hard String Sliding-Window Variable-Window Two-Pointers Hash-Map
LeetCode Problem Solving - Variable Size Sliding Window with Character Counting