AceStack AI Open interactive practice

Public task directory

Technical interview practice tasks

Every entry below is a crawlable link to a unique public task page. This directory complements the interactive filters and keeps the complete catalog connected through standard pagination.

Page 1 of 386 · 18,491 tasks

Coding (Algo) · Medium · 30 min

Navigation Breadcrumbs

Algorithm: Ancestor traversal Difficulty: Medium Time: 30 minutes Goal Return root-to-page IDs or null when the target is missing, a parent is missing or a cycle is encountered.

Coding (Algo) · Easy · 25 min

Missing Upload Sequence

Algorithm: Arithmetic Difficulty: Easy Time: 25 minutes Goal Return the missing sequence number without sorting the batch.

Coding (Algo) · Easy · 20 min

Remove an Entry from the End

Algorithm: Arrays Difficulty: Easy Time: 20 minutes Goal Return the values after removing exactly the nth entry from the end while preserving the order of the others.

Coding (Algo) · Medium · 40 min

Count Exact Size Selections

Algorithm: Backtracking Difficulty: Medium Time: 40 minutes Goal Count subsets of exactly k distinct indexes whose values sum to the target amount.

Coding (Algo) · Hard · 55 min

Count Non Attacking Queen Placements

Algorithm: Backtracking Difficulty: Hard Time: 55 minutes Goal Count every valid full-board queen placement with no shared row, column or diagonal.

Coding (Algo) · Medium · 40 min

Count Selections With a Target Mask

Algorithm: Backtracking Difficulty: Medium Time: 40 minutes Goal Count index subsets whose combined XOR equals the target, including the empty selection when appropriate.

Coding (Algo) · Easy · 25 min

Count Records Inside a Value Range

Algorithm: Binary search Difficulty: Easy Time: 25 minutes Goal Count all entries between the supplied lower and upper bounds including both endpoints.

Coding (Algo) · Easy · 25 min

Find the First Matching Record

Algorithm: Binary search Difficulty: Easy Time: 25 minutes Goal Find the first exact occurrence of the target in the sorted keys or report that it is absent.

Coding (Algo) · Easy · 25 min

Find the Insertion Position

Algorithm: Binary search Difficulty: Easy Time: 25 minutes Goal Return the first index whose value is at least target, or nums.length if no such index exists.

Coding (Algo) · Easy · 25 min

Find the Nearest Available Value

Algorithm: Binary search Difficulty: Easy Time: 25 minutes Goal Return the allowed value closest to the target and choose the smaller value on an equal-distance tie.

Coding (Algo) · Easy · 25 min

Find the Position After Equal Values

Algorithm: Binary search Difficulty: Easy Time: 25 minutes Goal Return the first index whose value is strictly greater than the target code.

Coding (Algo) · Medium · 40 min

Find the Smallest Daily Shipping Capacity

Algorithm: Binary search Difficulty: Medium Time: 40 minutes Goal Return the minimum whole-number capacity that ships every package within the allowed number of days.

Coding (Algo) · Medium · 40 min

Longest Rising Sequence

Algorithm: Binary search Difficulty: Medium Time: 40 minutes Goal Return the length of the longest strictly increasing subsequence without reconstructing the chosen values.

Coding (Algo) · Medium · 45 min

Record History Queries

Algorithm: Binary search Difficulty: Medium Time: 45 minutes Goal Build an in-memory revision index and answer each record lookup at its own cutoff time.

Coding (Algo) · Medium · 45 min

Search Prefix Suggestions

Algorithm: Binary search Difficulty: Medium Time: 45 minutes Goal Return suggestions after each added character.

Coding (Algo) · Medium · 30 min

Validate a Search Index

Algorithm: Binary search tree Difficulty: Medium Time: 30 minutes Goal Return whether every reachable node satisfies the strict binary-search ordering against all of its ancestors.

Coding (Algo) · Hard · 60 min

Virtual List Offsets

Algorithm: Binary search Difficulty: Hard Time: 60 minutes Goal Apply row-height updates and answer the pixel offset immediately before a requested row.

Coding (Algo) · Hard · 60 min

Weighted Job Schedule

Algorithm: Binary search Difficulty: Hard Time: 60 minutes Goal Return the maximum value of a non-overlapping subset of jobs.

Coding (Algo) · Hard · 65 min

Compatible Worker Assignment

Algorithm: Bipartite matching Difficulty: Hard Time: 65 minutes Goal Return the maximum number of jobs that can run at once with one job per worker.

Coding (Algo) · Hard · 45 min

Maximize Compatible Assignments

Algorithm: Bipartite matching Difficulty: Hard Time: 45 minutes Goal Return the largest number of compatible pairs such that no left item or right reviewer is used more than once.

Coding (Algo) · Easy · 25 min

Combine a Batch of Status Masks

Algorithm: Bit manipulation Difficulty: Easy Time: 25 minutes Goal Combine every input mask with XOR and return the result as one unsigned 32-bit integer.

Coding (Algo) · Easy · 25 min

Count Enabled Flags Across Records

Algorithm: Bit manipulation Difficulty: Easy Time: 25 minutes Goal Count all set bits across every supplied 32-bit mask and return their total.

Coding (Algo) · Easy · 25 min

Count Similar Configuration Pairs

Algorithm: Bit manipulation Difficulty: Easy Time: 25 minutes Goal Count unordered pairs of distinct record indexes whose masks differ in at most k bits.

Coding (Algo) · Hard · 55 min

Find the Most Different Mask Pair

Algorithm: Bit manipulation Difficulty: Hard Time: 55 minutes Goal Return the largest unsigned XOR attainable using two different input indexes.

Coding (Algo) · Easy · 20 min

Find the Unpaired Value

Algorithm: Bit manipulation Difficulty: Easy Time: 20 minutes Goal Return the single integer that occurs once using constant extra memory.

Coding (Algo) · Easy · 20 min

Find the Shared Name Prefix

Algorithm: Boundary handling Difficulty: Easy Time: 20 minutes Goal Return the longest case-sensitive prefix shared by every supplied name without changing or reordering the names.

Coding (Algo) · Medium · 30 min

Read a Matrix in Spiral Order

Algorithm: Boundary traversal Difficulty: Medium Time: 30 minutes Goal Return a flat array of all matrix values in clockwise spiral order without modifying the matrix.

Coding (Algo) · Medium · 35 min

Find a Rank With Bounded Storage

Algorithm: Bounded heap Difficulty: Medium Time: 35 minutes Goal Return the kth largest value with duplicates counted as separate positions while using at most O(k) additional storage.

Coding (Algo) · Medium · 35 min

Keep the Largest Batch Values

Algorithm: Bounded heap Difficulty: Medium Time: 35 minutes Goal Return the largest min(k,n) values in descending numeric order while retaining duplicate occurrences and using only bounded.

Coding (Algo) · Medium · 35 min

Keep the Nearest Measurements

Algorithm: Bounded heap Difficulty: Medium Time: 35 minutes Goal Return up to k values ordered by distance to target then value then original index using O(k) additional selection storage.

Coding (Algo) · Hard · 65 min

Map Repair Budget

Algorithm: Breadth first search Difficulty: Hard Time: 65 minutes Goal Find the fewest moves from the top-left to bottom-right cell with at most k obstacle entries.

Coding (Algo) · Medium · 35 min

Shortest Clear Grid Route

Algorithm: Breadth first search Difficulty: Medium Time: 35 minutes Goal Return the minimum number of moves from the top-left to the bottom-right clear cell or -1 if no route exists.

Coding (Algo) · Medium · 40 min

Visit Reachable Nodes in Queue Order

Algorithm: Breadth first search Difficulty: Medium Time: 40 minutes Goal Return the breadth-first visitation sequence from source while considering each visited node’s outgoing neighbors in.

Coding (Algo) · Easy · 15 min

Reverse an ASCII Line

Algorithm: Character order Difficulty: Easy Time: 15 minutes Goal Return the same ASCII characters in reverse order preserving every space and punctuation character.

Coding (Algo) · Medium · 40 min

Count Distinct Batch Orderings

Algorithm: Combinatorics Difficulty: Medium Time: 40 minutes Goal Count distinct value orderings that use every input occurrence exactly once.

Coding (Algo) · Medium · 40 min

Count Review Panels

Algorithm: Combinatorics Difficulty: Medium Time: 40 minutes Goal Return the exact number of distinct unordered panels of size k drawn from n reviewers.

Coding (Algo) · Medium · 40 min

Detect a Connection Cycle

Algorithm: Cycle detection Difficulty: Medium Time: 40 minutes Goal Return whether any component contains a cycle under the declared directed or undirected multigraph rules.

Coding (Algo) · Medium · 35 min

Find the First Repeated Link

Algorithm: Cycle detection Difficulty: Medium Time: 35 minutes Goal Return the index where the reachable chain first enters its cycle using constant auxiliary space or null if the chain.

Coding (Algo) · Hard · 65 min

Critical Service Links

Algorithm: Depth first search Difficulty: Hard Time: 65 minutes Goal Return every bridge edge by its original input index.

Coding (Algo) · Easy · 20 min

Depth of a Nested Index

Algorithm: Depth first search Difficulty: Easy Time: 20 minutes Goal Return the number of reachable nodes on the longest path from the root to a leaf.

Coding (Algo) · Easy · 25 min

Find a Complete Path Total

Algorithm: Depth first search Difficulty: Easy Time: 25 minutes Goal Return whether at least one reachable root-to-leaf path has node values summing exactly to target.

Coding (Algo) · Hard · 50 min

Count Cheapest Delivery Routes

Algorithm: Dijkstra Difficulty: Hard Time: 50 minutes Goal Count distinct directed routes from source to target whose total weight is minimal while treating parallel edges as distinct.

Coding (Algo) · Medium · 40 min

Find the Cheapest Directed Route

Algorithm: Dijkstra Difficulty: Medium Time: 40 minutes Goal Return the minimum sum of edge weights from source to target or null when no valid route connects them.

Coding (Algo) · Medium · 40 min

List Destinations Within Budget

Algorithm: Dijkstra Difficulty: Medium Time: 40 minutes Goal Return reachable node labels whose minimum route cost does not exceed budget ordered by minimum cost and then numeric label.

Coding (Algo) · Medium · 40 min

Count Out of Order Record Pairs

Algorithm: Divide and conquer Difficulty: Medium Time: 40 minutes Goal Count pairs of original indexes i < j for which the earlier value is strictly greater than the later value.

Coding (Algo) · Medium · 40 min

Choose a Shipping Load

Algorithm: Dynamic programming Difficulty: Medium Time: 40 minutes Goal Return the maximum benefit achievable without exceeding capacity or selecting any package more than once.

Coding (Algo) · Medium · 40 min

Choose Nonadjacent Maintenance Slots

Algorithm: Dynamic programming Difficulty: Medium Time: 40 minutes Goal Return the greatest total benefit of a subset that never selects adjacent schedule positions.

Coding (Algo) · Medium · 35 min

Choose the Most Valuable Bookings

Algorithm: Dynamic programming Difficulty: Medium Time: 35 minutes Goal Return the maximum sum of values for a set of pairwise non-overlapping half-open bookings without forcing selection of.