Types of Dynamic Programming Questions

Dynamic programming is probably the trickiest and most-feared interview question type. The hardest parts are 1) to know it’s a dynamic programming question to begin with 2) to find the subproblem.

We looked at a ton of dynamic programming questions and summarized common patterns and subproblems.

We also highlighted the keywords that indicate it’s likely a dynamic programming problem.

Sequence

  • House robber — find maximum amount of loot
  • Coin change — find minimum amount of coins needed to make up an amount

Grid

  • Robot unique paths — number of ways for robot to move from top left to bottom right
  • Min path sum — find path in a grid with minimum cost
  • Maximal square — find maximal square of 1s in a grid of 0s and 1s

Dynamic number of subproblems

  • Longest Increasing Subsequence — find the longest increasing subsequence of an array of numbers
  • Buy/sell stock with at most K transactions — maximize profit by buying and selling stocks using at most K transaction

Partition

  • Decode ways — how many ways to decode a string
  • Word break — partition a word into words in a dictionary
  • Triangle — find the smallest sum path to traverse a triangle of numbers from top to bottom
  • Partition to Equal Sum Subsets — partition a set of numbers into two equal-sum subsets

Two Sequences

  • Edit distance — find the minimum distance to edit one string to another
  • Longest common subsequence — find the longest common subsequence that is common in two sequences

Game theory

  • Coins in a line
  • Divisor game
  • Stone game

Learn more about each type with detailed analysis and illustrations at AlgoMonster:

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