Intern Sprint roadmap
Two weeks, about three a day: the easy and medium patterns online assessments use most.
For: Applying for internships and new-grad roles
Arrays and Hashing
Trade memory for speed by remembering what you have already seen.
Strings
Scan, compare and rebuild text with counters, windows and pointers.
Two Pointers
Walk a sequence from both ends, or at two speeds, to avoid nested loops.
Stack
Last in, first out. Use it to match pairs and undo work.
Sliding Window
Keep a moving range valid while you slide it across the input.
- Best Time to Buy and Sell Stock
- Maximum Average Subarray I
- Longest Substring Without Repeating Characters
Binary Search
Halve the search space each step, on sorted data or on an answer range.
Linked List
Rewire pointers in place, and use fast and slow pointers to find cycles and middles.
Trees
Think recursively: solve a node from the answers for its children.
- Invert Binary Tree
- Maximum Depth of Binary Tree
- Symmetric Tree
- Binary Tree Level Order Traversal
- Validate Binary Search Tree
Heap / Priority Queue
Always get the smallest or largest item next without sorting everything.
Graphs
Traverse connected structures: islands, components, shortest hops in a grid.
Backtracking
Build candidates step by step and undo a choice when it cannot lead to an answer.
1-D Dynamic Programming
Break a problem into overlapping subproblems and store each answer once.