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If the coin change problem is extended to allow fractional coin denominations (e.g., 0.25, 0.5) and a fractional target amount, which approach is most appropriate to find the minimum number of coins?

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Dynamic Programming: Knapsack - Coin Change (Minimum Coins)
If the coin change problem is extended to allow fractional coin denominations (e.g., 0.25, 0.5) and a fractional target amount, which approach is most appropriate to find the minimum number of coins?
AConvert to integer problem by scaling and apply DP
BUse a greedy algorithm with sorting
CUse standard integer DP without modifications
DApply graph shortest path algorithms directly
Step-by-Step Solution
Solution:
  1. Step 1: Understand fractional denominations

    DP requires integer indices; fractional amounts complicate direct DP.
  2. Step 2: Scale problem

    Multiply all coin values and amount by a factor (e.g., 100) to convert to integers.
  3. Step 3: Apply integer DP

    Use standard DP on scaled integers to find minimum coins.
  4. Final Answer:

    Option A -> Option A
  5. Quick Check:

    Scaling preserves problem structure for DP [OK]
Quick Trick: Scale fractional amounts to integers before DP [OK]
Common Mistakes:
MISTAKES
  • Applying DP directly on floats
  • Assuming greedy always works
  • Ignoring precision issues
Trap Explanation:
PITFALL
  • Ignoring scaling leads to incorrect DP indexing and results
Interviewer Note:
CONTEXT
  • Tests ability to adapt DP solutions to fractional inputs
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