Fundamental data structure patterns for manipulating sequential data. Master these basics as they fo...

Build solutions incrementally, abandoning paths that cannot lead to valid solutions....

Divide search space in half each iteration. Works on sorted arrays or when searching for optimal val...

DP = Recursion + Memoization (or Tabulation). Start by solving recursively, then optimize. The key i...

Make the locally optimal choice at each step, hoping to find the global optimum. Unlike DP, greedy a...

Network of nodes and edges. Key algorithms: DFS, BFS, topological sort, Union-Find, Dijkstra....

Use hash tables for O(1) average lookups, frequency counting, and duplicate detection. Foundation fo...

Efficiently track min/max elements. Essential for top K, streaming median, and scheduling....

Problems involving ranges with start/end points. Key: sort by start or end time....

Sequential data structure with node-based traversal. Key techniques: reversal, fast/slow pointers, d...

Precompute cumulative sums to answer range sum queries in O(1). Combined with HashMap for finding su...

Maintain a window of elements that slides through the array. Track window state efficiently by addin...

LIFO structure for matching pairs, expression evaluation, and finding next greater/smaller elements ...

Hierarchical data structure. Master DFS (preorder, inorder, postorder) and BFS (level order) travers...

Tree structure for efficient string prefix operations. Each node represents a character....

Use two pointers to traverse data from different positions, often from both ends moving toward cente...

Track disjoint sets efficiently. Supports union (merge) and find (membership)....