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Study the first family—Traversal and connectivity—plus LC 1–100 and every candidate problem related to that family.

1open family
100LC 1–100 routes
541Free problem pages

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First family

Four full patterns with invariants, code skeletons, and related problems.

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LC 1–100

Search candidate routes by ID, title, tags, or template.

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All Free problems

The union of LC 1–100 and first-family candidates: 541 problems.

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Pattern families

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Traversal and connectivity

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Ordered frontier and path

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Binary search and monotone answer

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Pointers and sliding window

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Prefix, difference, and hashed state

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Stack and monotone deque

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Heap, selection, and stream

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Greedy and scheduling

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Divide and conquer

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Dynamic programming

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Backtracking and constraint search

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Tree, BST, and trie

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DSU, MST, and offline activation

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Range-query data structures

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String matching, hashing, and palindrome

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Math, number theory, and combinatorics

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Bit manipulation and bitmask state

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Geometry, sweep, simulation, and parsing

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