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834 questions across 64 roles. Open one to see what a strong answer includes and common slips, then drill it out loud with Ava. New to answer structure? Start with the learning hub.

572 questions match your filters.

TechnicalMid levelAny software role
Coding problem: Sliding-Window Rate Limiter. An API lets each client make at most `limit` accepted requests in any window of `window_ms` milliseconds. You get the incoming `requests` as `[client_id, timestamp_ms]` pairs in time order. Decide, in order, whether each request is accepted, and return a list of booleans.
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Diff Lists by ID. A UI keeps a list of items, each an object with a unique integer `id` plus other fields. Given the list `before` and the list `after`, return an object `{"added": [...], "removed": [...], "changed": [...]}` of ids:
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Search a Rotated List. A list of distinct integers was sorted in increasing order and then rotated: some prefix was moved to the end, so `[1, 3, 5, 8, 9]` might have become `[8, 9, 1, 3, 5]`. Given the rotated list `nums` and an integer `target`, return the index of `target` in `nums`, or `-1` if it isn't there.
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Fewest Steps Through a Warehouse. A warehouse floor is a grid given as a list of strings, one per row: `.` is open floor and `#` is a shelf. A robot starts in the top-left cell and must reach the bottom-right cell. Each step moves it one cell up, down, left or right; it can't move onto a shelf or off the grid.
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Build Order. There are `n` build tasks numbered `0` to `n - 1`. Each pair `[a, b]` in `deps` means task `a` must finish before task `b` can start. Return an order in which all the tasks can run, one at a time.
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Fewest Coins. Given coin values `coins` (with an unlimited supply of each) and a target `amount`, return the smallest number of coins that add up to exactly `amount`, or `-1` if it can't be done.
Tests: Problem solving
TechnicalMid levelAny software role
Coding problem: Cheapest Delivery Route. A delivery network is given as an adjacency list: `graph` maps each depot name to a list of `[neighbor, cost]` pairs, one for each one-way road leaving that depot. Costs are non-negative integers. Return the lowest total cost of a route from `start` to `goal`, or `-1` if there's no route.
Tests: Problem solving
TechnicalSeniorAny software role
Coding problem: Fewest Edits Between Strings. Return the minimum number of single-character edits that turn the string `a` into the string `b`. One edit inserts a character, deletes a character, or replaces one character with another.
Tests: Problem solving
TechnicalSeniorAny software role
Coding problem: Calculator Without eval. Evaluate an arithmetic expression given as a string and return its integer value. The expression contains non-negative integers, the operators `+`, `-`, `*` and `/`, parentheses and spaces.
Tests: Problem solving
TechnicalSeniorAny software role
Coding problem: Rainwater Between Walls. `heights` lists the heights of walls of width 1 standing side by side. After heavy rain, water fills every dip that has taller walls on both sides; anything above the outer edges runs off. Return the total units of water held.
Tests: Problem solving
TechnicalSeniorAny software role
Coding problem: Moving Median. Given a list of integers `values` and a window size `k`, return the median of every window of `k` consecutive values, from left to right. There are `len(values) - k + 1` windows; return an empty list when `k` is larger than the list.
Tests: Problem solving
TechnicalSeniorAny software role
Coding problem: Budget Combinations. You have a list of item `prices` (positive integers, possibly repeated) and a `budget`. Find every distinct combination of items whose prices add up to exactly `budget`, using each item at most once.
Tests: Problem solving