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Coin Change

Detailed guide and Python implementation for the 'Coin Change' problem.

Problem Statement

Medium

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money.

Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1.

You may assume that you have an infinite number of each kind of coin.

Write a function coinChange(coins: List[int], amount: int) -> int.

Constraints
  • 1 <= len(coins) <= 12
  • 1 <= coins[i] <= 2^31 - 1
  • 0 <= amount <= 10^4

Examples

Example 1
Input
coins = [1,2,5], amount = 11
Output
3
Explanation

11 = 5 + 5 + 1

Example 2
Input
coins = [2], amount = 3
Output
-1
Explanation

3 cannot be formed using only coins of denomination 2.

Example 3
Input
coins = [1], amount = 0
Output
0
Explanation

No coins are needed to make amount 0.

Need a Hint?
Consider using 1D DP-specific data structures like sets or heaps.
Edge Cases to Watch
  • Empty input structures
  • Single element inputs
  • Large numerical bounds

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