Volume 64 (6,400-6,499)

Problem ID Title Solution by Most Popular Input by
6400 Matryoshka
6401 Pirate Chest
6402 Pollution Solution
6403 Up a Tree
6404 Secure PINs
6405 The Large Family
6406 Start-Up Network
6407 Clock Splitter
6408 Neocortex Order
6409 Some Pretty Peculiar Cells
6410 Mealy's Memoirs
6411 Ninja Pizza
6412 Count the Squares
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6413 Yet Another Newspaper Puzzle
6414 Encyclopaedia
6415 Solar Powered Ants
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6416 Isle of the Birds
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6417 Street Lights
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6418 Fitness Training
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6419 Matchstick Maths
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6420 Similarity
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6421 Railways
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6422 Necklace
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6423 Student IDs
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6424 Russian Dolls
6425 Intercity
6426 Count (2)
6427 Chess (2)
6428 A+B (2)
6429 Dragon Pattern
6430 Points (2)
6431 Red John Game
6432 Influence
6433 An Idea of Mr. A
6434 Number Assignment
6435 Network Packet Ordering
6436 The Busiest City
6437 Power Plant
6438 Railroad (2)
6439 Pasti Pas!
6440 Emergency Handling
6441 Horrible Quiz
6442 Coins on a Ring
6443 Alien Abduction Again
6444 Fast Food Prizes
6445 Seven Kingdoms
6446 Institute of Advanced Category Manipulation
6447 Digital Content Protection
6448 Credit Card Payment
6449 IQ Test
6450 Social Advertising
6451 Tables
6452 Flood-It
6453 Chemicals Monitoring
6454 Lights Against Dudely
6455 Stealing Harry Potter's Precious
6456 Zhuge Liang's Password
6457 Problem of Apollonius
6458 Random Number Generator
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6459 Infinite Go
6460 Ants (2)
6461 Rabbit Kingdom
6462 Gems Fight!
6463 Tower Defense
6464 Candy Factory
6465 Islands in the Data Stream (1)
6466 Von Neumann's Fly
6467 Strahler Order
6468 Pisano Periods
6469 Deranged Exams
6470 Chomp
6471 Triangle Count Sequences of Polygon Triangulations
6472 Powers of Pascal
6473 Contraband
6474 Drop Zone
6475 Effective Infection Time
6476 Outpost Navigation
6477 Multikill
6478 Virology
6479 Worst Case Scenario
6480 Zombie Invasion
6481 Zombdar
6482 Beautiful Mountains
6483 Nested Palindromes
6484 Ping!
6485 Electric Car Rally
6486 Skyscrapers (2)
6487 Star Simulations
6488 Tandem Repeats
6489 Triangles (4)
6490 It Takes a Village
6491 You Win!
6492 Welcome Party
6493 Round Robin
6494 Missing Pages
6495 Probability Paradox
6496 Letter Cubes
6497 Digit Sum
6498 Cash Cow
6499 Sort Me