Solving Coin Change using Unbounded knapsack.

Problem

Minimum coins for amount.

Pattern

This problem demonstrates the Unbounded knapsack pattern.

Approach

Bottom-up DP over amounts.

Solution 

  // Solution for Coin Change
// Pattern: Unbounded knapsack
// O(amount × coins) time

Complexity

O(amount × coins) time

Best Practices

  • Identify the pattern before coding — pattern recognition saves time
  • Handle edge cases: empty input, single element, duplicates
  • Use descriptive variable names even in timed interviews
  • Test with the provided examples plus one custom case