Arrays & Strings
← All learning paths
Progress from frequency maps and pointer scans to windows, prefixes, and monotonic structures.
Outcome: Choose the right linear-time pattern for sequence problems.
Recommended first: Coding Foundations
Module 1: Counting & Prefixes
Reuse aggregate information instead of rescanning.
0/7
Module 2: Two Pointers
Move boundaries deliberately while preserving invariants.
0/5
Module 3: Windows & Monotonic Structures
Maintain only the state needed by the current range.
0/8
1
Best Time to Buy and Sell Stock
easy
Not started
2
Longest Substring Without Repeating Characters
medium
Not started
3
Valid Parentheses
easy
Not started
4
Min Stack
medium
Not started
5
Daily Temperatures
medium
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6
Largest Rectangle in Histogram
hard
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7
Sliding Window Maximum
hard
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8
Minimum Window Substring
hard
Not started
