Coding interview problems

3,736 problems: 937 Easy, 1,914 Medium, 885 Hard. Each runs against hidden tests, in 13 languages; database problems in SQL. Free for members.

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Problems 501–600 of 3,736

501. Minimum Flock Size Medium · Array, Hash Table, Math, Greedy
502. Shortest All-Ones Multiple Medium · Math, Hash Table
503. Fraction as Decimal Text Medium · Math, String, Hash Table · 0% accepted
504. Palindrome from Two-Letter Blocks Medium · Array, String, Hash Table, Greedy, Counting
505. Even Variety Splits Medium · String, Hash Table
506. Players by Losses Medium · Array, Hash Table, Sorting, Counting
507. Square Corner Counter Medium · Array, Hash Table, Design, Counting
508. Longest Substring with Each Letter K+ Times Medium · String, Hash Table, Divide and Conquer, Sliding Window
509. Same Alphabet Pairs Medium · Array, String, Hash Table, Bit Manipulation
510. Best Equal Digit-Sum Pair Medium · Array, Hash Table, Math
511. Earliest Dominant Split Medium · Array, Hash Table, Counting
512. Shared Prefix Counts Medium · Array, Hash Table, Bit Manipulation
513. Twin Distance Totals Medium · Array, Hash Table, Prefix Sum
514. Pair Counter with Updates Medium · Array, Hash Table, Design
515. Container Index Lookup Medium · Hash Table, Heap (Priority Queue), Design
516. Scoreboard Top K Medium · Hash Table, Sorting, Design, Heap (Priority Queue)
517. Frequency Tracker Medium · Hash Table, Design, Counting
518. Duplicate Content Groups Medium · Array, String, Hash Table
519. Domain Visit Totals Medium · Array, String, Hash Table, Counting
520. Flagged Transactions Medium · Array, String, Hash Table
521. Frequent Badge Users Medium · Array, String, Hash Table, Sorting
522. Longest Stepwise-Built Word Medium · Array, String, Hash Table, Sorting
523. Shorten Words to Roots Medium · Array, String, Hash Table
524. One-Edit Dictionary Matches Medium · Array, String, Hash Table
525. Most Frequent Bounded Substring Medium · String, Hash Table, Sliding Window
526. Smallest Clean Card Back Medium · Array, Hash Table
527. Longest Square Chain Medium · Array, Hash Table, Sorting
528. Power-of-Two Pairs Medium · Array, Hash Table, Counting
529. Distinct Three-Letter Palindromes Medium · String, Hash Table
530. Mirror Line Check Medium · Array, Hash Table, Math
531. Largest Union After Halving Medium · Array, Hash Table, Greedy
532. Form Groups by Requested Size Medium · Array, Hash Table, Greedy
533. Active Minute Histogram Medium · Array, Hash Table
534. Uniform Rows After Column Flips Medium · Array, Hash Table, Matrix
535. Anti-Diagonal Order of Ragged Rows Medium · Array, Hash Table, Sorting
536. Fewest Kinds to Halve Medium · Array, Hash Table, Greedy, Sorting
537. Color Variety After Each Paint Medium · Array, Hash Table, Simulation
538. Range Value Counts Medium · Array, Hash Table, Binary Search
539. Best Endpoint-Gap Subarray Sum Medium · Array, Hash Table, Prefix Sum
540. Balance Variety with One Swap Medium · String, Hash Table, Counting
541. Subarrays with Many Twins Medium · Array, Hash Table, Sliding Window
542. Distinct Subarray ORs Medium · Array, Hash Table, Bit Manipulation, Dynamic Programming
543. Edits for an Alternating Pattern Medium · Array, Hash Table, Greedy, Counting
544. Most Disjoint Target Subarrays Medium · Array, Hash Table, Prefix Sum, Greedy
545. Distinct Values per Window Medium · Array, Hash Table, Sliding Window
546. Longest Shared Segment Medium · Array, Hash Table, Binary Search
547. Right-Angle Cell Triples Medium · Array, Hash Table, Matrix, Counting
548. Robot Farthest Reach Medium · Array, Hash Table, Simulation
549. Garden Lights After Many Nights Medium · Array, Hash Table, Simulation, Bit Manipulation
550. Two Disjoint Target Subarrays Medium · Array, Hash Table, Prefix Sum, Dynamic Programming
551. Concatenation Pairs for a Target Medium · Array, String, Hash Table, Counting
552. Shortest Unique Snippet per Word Medium · Array, String, Hash Table
553. Best Pair XOR Medium · Array, Hash Table, Bit Manipulation
554. Longest Growing Word Chain Medium · Array, String, Hash Table, Dynamic Programming
555. Restore a Sequence from Neighbor Pairs Medium · Array, Hash Table
556. Mismatches After Allowed Swaps Medium · Array, Hash Table, Union Find, Counting
557. Expiring Cache Medium · Hash Table, Design, Simulation
558. Wraparound Alphabet Substrings Medium · String, Hash Table, Dynamic Programming
559. Distinct Doubled Substrings Hard · String, Hash Table
560. Longest Evenable Prefix Hard · Array, Hash Table, Counting
561. Longest Shufflable Palindrome of Digits Hard · String, Hash Table, Bit Manipulation, Prefix Sum
562. Fewest Changes to a Consecutive Run Hard · Array, Hash Table, Sorting, Sliding Window
563. Subarrays with More Ones than Zeros Hard · Array, Hash Table, Prefix Sum, Dynamic Programming
564. Fewest Swaps to Match Hard · String, Hash Table, Breadth-First Search
565. Sliding Tile Moves Hard · Array, Hash Table, Breadth-First Search, Matrix
566. Hop Across the River Hard · Array, Hash Table, Dynamic Programming
567. Tally Elements in a Formula Hard · String, Hash Table, Stack, Sorting
568. Most Sortable Chunks Hard · Array, Hash Table, Sorting, Counting
569. Puzzle Word Counts Hard · Array, String, Hash Table, Bit Manipulation
570. Distinct Non-Empty Subsequences Hard · String, Hash Table, Dynamic Programming
571. Tightest Range Across Lists Hard · Array, Hash Table, Sliding Window, Sorting, Heap (Priority Queue)
572. Seat Swaps for Partners Hard · Array, Hash Table, Greedy, Union Find
573. Most Mirror Chunks Hard · String, Hash Table, Greedy, Two Pointers
574. Shortest Front-Padded Palindrome Hard · String, Hash Table
575. Border Word Pairs Hard · Array, String, Hash Table
576. Grid Paths with a Target XOR Hard · Array, Hash Table, Matrix, Bit Manipulation
577. Split Halves Closest Hard · Array, Hash Table, Binary Search, Bit Manipulation
578. Tallest Even Pillars Hard · Array, Hash Table, Dynamic Programming
579. Complete Letter Substrings Hard · String, Hash Table, Sliding Window
580. Total Sorted Gaps Hard · Array, Hash Table
581. Count Clean Partitions Hard · Array, Hash Table, Math
582. Two-Swap Number Twins Hard · Array, Hash Table, Sorting
583. Best-Beauty Letter Subsequences Hard · String, Hash Table, Math, Greedy
584. Square Chain Permutations Hard · Array, Hash Table, Backtracking, Math
585. Build Word Squares Hard · Array, String, Hash Table, Backtracking
586. Compound Words Hard · Array, String, Hash Table, Dynamic Programming
587. Fewest Label Sheets Hard · Array, String, Hash Table, Dynamic Programming, Memoization
588. Palindromic Tree Paths Hard · Tree, Hash Table, Bit Manipulation, Depth-First Search
589. Mode of Every Window Hard · Array, Hash Table, Sliding Window, Design
590. Even-Occurrence Subarrays Hard · Array, Hash Table, Prefix Sum, Bit Manipulation
591. Permutation Subarrays Hard · Array, Hash Table
592. Rearrangement Queries Hard · Array, Hash Table, Prefix Sum
593. Distinct Subtree Shapes Hard · Tree, Hash Table, Depth-First Search, Sorting
594. Escape the Blockade Hard · Array, Hash Table, Breadth-First Search
595. Scoped Expression Evaluator Hard · String, Hash Table, Stack, Recursion
596. Transactional Key-Value Store Hard · String, Hash Table, Design, Stack
597. Multi-Pattern Scramble Counts Hard · String, Hash Table, Sliding Window
598. Distinct Palindromic Substrings Hard · String, Hash Table
599. Period Queries Hard · String, Hash Table
600. Largest Repeated Square Block Hard · Array, Hash Table, Binary Search, Matrix