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 4 of 386 · 18,491 tasks

Coding (Algo) · Hard · 65 min

Discounted Service Route

Algorithm: Shortest path Difficulty: Hard Time: 65 minutes Goal Find the minimum source-to-target cost when at most one traversed connection may cost floor(cost / 2).

Coding (Algo) · Medium · 40 min

Explain Unused Route Connections

Algorithm: Shortest path Difficulty: Medium Time: 40 minutes Goal Return each edge’s source label and destination label with slack equal to distance[from] plus weight minus distance[to].

Coding (Algo) · Medium · 40 min

Find the Fewest Handoffs

Algorithm: Shortest path Difficulty: Medium Time: 40 minutes Goal Return the minimum number of directed edges from source to target or null if either endpoint is missing or the target is.

Coding (Algo) · Medium · 40 min

Offline Map Distance

Algorithm: Shortest path Difficulty: Medium Time: 40 minutes Goal Return the shortest walk length or null when no walk exists.

Coding (Algo) · Medium · 45 min

Shortest Delivery Costs

Algorithm: Shortest path Difficulty: Medium Time: 45 minutes Goal Return minimum directed path costs from source in hub-ID order. Do not return paths or confuse a direct link with the.

Coding (Algo) · Medium · 40 min

Accepted Request Window

Algorithm: Sliding window Difficulty: Medium Time: 40 minutes Goal Return one acceptance decision per arrival.

Coding (Algo) · Medium · 35 min

Affordable Replay Window

Algorithm: Sliding window Difficulty: Medium Time: 35 minutes Goal Return the longest contiguous window whose total size is at most budget.

Coding (Algo) · Medium · 40 min

Count Periods With Exactly K Event Types

Algorithm: Sliding window Difficulty: Medium Time: 40 minutes Goal Return the count of non-empty contiguous segments containing exactly k distinct values.

Coding (Algo) · Medium · 35 min

Distinct Activity Window

Algorithm: Sliding window Difficulty: Medium Time: 35 minutes Goal Return the length of the longest contiguous subarray containing distinct kinds.

Coding (Algo) · Medium · 40 min

Find the Longest Limited Variety Period

Algorithm: Sliding window Difficulty: Medium Time: 40 minutes Goal Return the maximum length of a contiguous segment with at most k distinct input values.

Coding (Algo) · Hard · 65 min

Live Latency Median

Algorithm: Sliding window Difficulty: Hard Time: 65 minutes Goal Return the median of every full fixed-width window.

Coding (Algo) · Medium · 30 min

Longest Distinct Run

Algorithm: Sliding window Difficulty: Medium Time: 30 minutes Goal Return the length of the longest contiguous substring of s with no repeated characters.

Coding (Algo) · Hard · 40 min

Peak in Every Window

Algorithm: Sliding window Difficulty: Hard Time: 40 minutes Goal Return the maximum of each length-k contiguous window in linear total time without changing the measurements.

Coding (Algo) · Medium · 40 min

Required Marker Windows

Algorithm: Sliding window Difficulty: Medium Time: 40 minutes Goal Return every start index of a fixed-length excerpt that contains exactly the required marker counts.

Coding (Algo) · Medium · 30 min

Shortest Target Range

Algorithm: Sliding window Difficulty: Medium Time: 30 minutes Goal Return the minimum length of a contiguous range whose sum is at least target, or 0 if none qualifies.

Coding (Algo) · Easy · 25 min

Choose Unique Prefix Suggestions

Algorithm: Sorting Difficulty: Easy Time: 25 minutes Goal Return at most k distinct dictionary words beginning with the exact prefix in ascending ASCII lexicographic order.

Coding (Algo) · Hard · 40 min

Count the Outer Boundary Corners

Algorithm: Sorting Difficulty: Hard Time: 40 minutes Goal Return the number of distinct convex-hull vertices after excluding duplicate coordinates and collinear interior points.

Coding (Algo) · Hard · 50 min

Find the Closest Coordinate Pair

Algorithm: Sorting Difficulty: Hard Time: 50 minutes Goal Return the minimum squared Euclidean distance between two different input indexes or null if fewer than two records exist.

Coding (Algo) · Easy · 25 min

Find the Closest Pair of Measurements

Algorithm: Sorting Difficulty: Easy Time: 25 minutes Goal Return the minimum absolute difference between values at two distinct input positions.

Coding (Algo) · Easy · 25 min

List the Largest Distinct Readings

Algorithm: Sorting Difficulty: Easy Time: 25 minutes Goal Return at most k distinct input values in strictly decreasing numeric order.

Coding (Algo) · Easy · 20 min

Rank Characters by Frequency

Algorithm: Sorting Difficulty: Easy Time: 20 minutes Goal Return distinct input characters ordered by descending occurrence count and then increasing ASCII code when counts tie.

Coding (Algo) · Easy · 25 min

Rank Records Without Losing Their Positions

Algorithm: Sorting Difficulty: Easy Time: 25 minutes Goal Return each original record’s zero-based position in a stable ascending ordering of all records.

Coding (Algo) · Medium · 40 min

Stable Feed Pagination

Algorithm: Sorting Difficulty: Medium Time: 40 minutes Goal Deduplicate by ID, keep the latest timestamp, sort newest first then smaller numeric ID, and paginate the full set.

Coding (Algo) · Easy · 15 min

Peak Request Latency

Algorithm: Stable ordering Difficulty: Easy Time: 15 minutes Goal Return the index of the largest latency, preferring the earliest on ties.

Coding (Algo) · Easy · 25 min

Balanced Delimiters

Algorithm: Stack Difficulty: Easy Time: 25 minutes Goal Return whether (), [] and {} are correctly paired and nested.

Coding (Algo) · Easy · 25 min

Cancel Adjacent Actions

Algorithm: Stack Difficulty: Easy Time: 25 minutes Goal Return the fully reduced action string.

Coding (Algo) · Easy · 25 min

Normalize a Virtual Path

Algorithm: Stack Difficulty: Easy Time: 25 minutes Goal Return the canonical absolute path after resolving empty segments, dot segments and parent navigation.

Coding (Algo) · Medium · 35 min

Remove Repeating Token Groups

Algorithm: Stack Difficulty: Medium Time: 35 minutes Goal Process the sequence from left to right and return the survivors after repeatedly deleting each completed group of k equal tokens.

Coding (Algo) · Medium · 35 min

Resolve Opposing Token Collisions

Algorithm: Stack Difficulty: Medium Time: 35 minutes Goal Return the stable surviving token sequence after all adjacent positive-then-negative collision boundaries are resolved.

Coding (Algo) · Easy · 20 min

Validate Nested Brackets

Algorithm: Stack Difficulty: Easy Time: 20 minutes Goal Return whether every opening bracket has a closing bracket of the same type in the correct nested order.

Coding (Algo) · Easy · 25 min

Compress Consecutive Status Characters

Algorithm: Stream processing Difficulty: Easy Time: 25 minutes Goal Return consecutive character runs as ordered pairs of the character and its run length.

Coding (Algo) · Hard · 75 min

Cyclic Dependency Groups

Algorithm: Strongly connected components Difficulty: Hard Time: 75 minutes Goal Partition a directed graph into strongly connected components.

Coding (Algo) · Hard · 55 min

Count Distinct Text Fragments

Algorithm: Suffix automata Difficulty: Hard Time: 55 minutes Goal Return the number of distinct non-empty contiguous substrings without constructing or storing all of those substrings.

Coding (Algo) · Medium · 35 min

Peak Worker Demand

Algorithm: Sweep line Difficulty: Medium Time: 35 minutes Goal Return the maximum number of simultaneously active jobs.

Coding (Algo) · Medium · 35 min

Check Dependency Feasibility

Algorithm: Topological sort Difficulty: Medium Time: 35 minutes Goal Return whether all n courses can be completed without violating any prerequisite relationship.

Coding (Algo) · Medium · 45 min

Deployment Critical Path

Algorithm: Topological sort Difficulty: Medium Time: 45 minutes Goal Return the earliest total completion time or null for a dependency cycle.

Coding (Algo) · Medium · 45 min

Form Dependency Order

Algorithm: Topological sort Difficulty: Medium Time: 45 minutes Goal Return the lexicographically smallest topological ordering of field IDs or null when a cycle exists.

Coding (Algo) · Medium · 40 min

Order Ready Jobs Deterministically

Algorithm: Topological sort Difficulty: Medium Time: 40 minutes Goal Return the lexicographically smallest ordering that places every prerequisite before its dependent job or null if no.

Coding (Algo) · Medium · 40 min

Parallel Initialization Batches

Algorithm: Topological sort Difficulty: Medium Time: 40 minutes Goal Return earliest possible batches sorted numerically within each batch, or null for a cycle.

Coding (Algo) · Easy · 20 min

Count Selected Tree Nodes

Algorithm: Tree traversal Difficulty: Easy Time: 20 minutes Goal Return the number of selected nodes reachable from the root while continuing through unselected parents.

Coding (Algo) · Medium · 25 min

Find the Shared Tree Ancestor

Algorithm: Tree traversal Difficulty: Medium Time: 25 minutes Goal Return the heap index of the lowest common ancestor of p and q or null if either selected index is absent or unreachable.

Coding (Algo) · Easy · 20 min

Measure the Busiest Tree Level

Algorithm: Tree traversal Difficulty: Easy Time: 20 minutes Goal Return the maximum number of reachable nodes at any one depth counting actual nodes rather than index gaps.

Coding (Algo) · Medium · 30 min

Measure the Longest Tree Route

Algorithm: Tree traversal Difficulty: Medium Time: 30 minutes Goal Return the greatest number of edges on any simple route between two reachable nodes in the tree.

Coding (Algo) · Easy · 25 min

Read Selected Tree Values

Algorithm: Tree traversal Difficulty: Easy Time: 25 minutes Goal Return the selected reachable values in inorder traversal order without sorting by their numeric value.

Coding (Algo) · Easy · 25 min

Summarize Tree Levels

Algorithm: Tree traversal Difficulty: Easy Time: 25 minutes Goal Return signed totals in increasing zero-based depth order with one entry for every reachable level.

Coding (Algo) · Easy · 20 min

Total Selected Tree Values

Algorithm: Tree traversal Difficulty: Easy Time: 20 minutes Goal Return the signed sum of selected reachable node values and ignore stale entries behind null parents.

Coding (Algo) · Hard · 65 min

Ranked Prefix Index

Algorithm: Trie Difficulty: Hard Time: 65 minutes Goal Precompute an index returning the best three matching words for every query.

Coding (Algo) · Medium · 35 min

Choose the Closest Three Entry Total

Algorithm: Two pointers Difficulty: Medium Time: 35 minutes Goal Return the closest sum obtainable from three different indexes and choose the smaller sum when distances to the target tie.