14 universal patterns that solve 80% of coding interview problems. Learn to recognise the pattern before writing a single line of code.
Fast/slow pointers, in-place reversal, and dummy-node techniques for singly linked list problems.
Monotonic stacks, bracket matching, and designing stack/queue-backed structures like LRU caches.
Choose-explore-unchoose backtracking for subsets, permutations, and constraint-satisfaction problems.
Practice problems
SubsetsMediumRecognizing when a locally-optimal choice provably leads to a globally-optimal answer.
Practice problems
Jump GameMediumBinary search beyond a plain sorted array — rotated arrays, answer-space search, and other disguised applications.
XOR tricks, bit counting, and the handful of bitwise idioms that recur across interview problems.
Practice problems
Single NumberEasyInterval merging, cyclic sort, and custom-comparator problems built on top of sorting.
