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NEURO-OS
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Daily OS
The Science
Syntax Sandbox
Type pattern templates from memory. 3 rounds per pattern. Accuracy before speed.
Select Pattern
Hash Map
O(1) Lookup
Need frequency, existence, or pairing. Input is unsorted.
Two Pointers
Monotonic
Input is sorted or needs in-place rearrangement.
Sliding Window
Contiguous
Problem asks for a contiguous subarray/substring.
Stack
LIFO / Monotonic
Need next greater/smaller, or deferred matching.
Binary Search
Halving
Array is sorted, or answer space is monotonic.
Linked List
Pointer
O(1) insertion/deletion or pointer manipulation required.
Trees
Hierarchical
Data is hierarchical (parent-child).
Heap
Priority
Need min/max element dynamically, or top K.
Backtracking
Combinatorial
Problem asks for all permutations/subsets/combinations.
Graphs
Network
Non-hierarchical network, dependencies, or grid traversal.
DP 1D
Optimal Substructure
Problem asks for max/min/count with overlapping subproblems.
DP 2D
Grid / Two Sequences
Decisions depend on two dimensions (grid, two strings).
Intervals
Range Coordination
Time ranges or start/end points need coordination.
Bit Manipulation
Binary
Powers of 2, parity, or uniqueness via XOR.
Greedy
Local Optimal
Problem asks for global optimum that can be built from local choices.