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Amazon Coding Interview

Amazon's greatest hits: hashing, two pointers, grids, and binary search on the answer.

Islands
10
Lessons
90
Exercises
311
Complete codeDebugCode orderMultiple choiceTapTrace
  1. Island 1

    Capacity to Ship Packages

    Ship packages in the given order within D days — each day loads consecutive packages up to the boat's capacity. Find the smallest capacity that ships them all in time.

    1. Decode the Problem3 exercises, 5 min
    2. Approach Check4 exercises, 5 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 5 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 6 min
    8. Test and Analyze3 exercises, 5 min
    9. Boss BattleBoss8 exercises, 8 min
  2. Island 2

    Number of Islands

    Given a grid of land ('1') and water ('0') cells, count the islands — regions of land connected horizontally or vertically.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  3. Island 3

    Two Sum

    Find the two numbers in an array that add up to a target, and return their indices.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  4. Island 4

    Trapping Rain Water

    Bars of varying heights trap rain between them — compute how much water the whole skyline holds.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  5. Island 5

    Course Schedule

    Given prerequisite pairs, decide whether every course can be finished — or whether the requirements loop forever.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze4 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  6. Island 6

    Rotting Oranges

    Rot spreads from bad oranges to neighbors each minute — find how long until no fresh orange remains, or prove some never rot.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  7. Island 7

    3Sum

    Find every unique triplet in an array that sums to zero — without listing the same triplet twice.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  8. Island 8

    Koko Eating Bananas

    Pick the slowest banana-eating speed that still finishes every pile before the guards return in h hours.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  9. Island 9

    Median of Two Sorted Arrays

    Two sorted arrays, one combined median — find it without actually merging them.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
  10. Island 10

    Longest Repeating Character Replacement

    You may repaint at most k letters — find the longest stretch you can turn into one repeated character.

    1. Decode the Problem3 exercises, 4 min
    2. Approach Check4 exercises, 4 min
    3. Build the Brute Force3 exercises, 5 min
    4. Find the Bottleneck2 exercises, 4 min
    5. Discover the Optimal Approach3 exercises, 4 min
    6. Assemble the Algorithm2 exercises, 5 min
    7. Read the Implementation3 exercises, 5 min
    8. Test and Analyze3 exercises, 4 min
    9. Boss BattleBoss8 exercises, 8 min
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Amazon Coding Interview is part of AlgoFox Pro

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