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Back to ChallengesCoin Change IIHard 30 min

Coin Change II

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. Return the number of combinations that make up that amount.

Examples

Input: amount = 5, coins = [1,2,5]
Output: 4
Combinations are: 5, 2+2+1, 2+1+1+1, 1+1+1+1+1

Constraints

  • • 1 <= coins.length <= 300
  • • 1 <= coins[i] <= 5000
  • • 0 <= amount <= 5000

Complexity Analysis

Time
O(coins.length * amount)
loops to accumulate possible sums.
Space
O(amount)
DP array storing paths count for each amount.

Test Cases

#1 Standard amount combinations
Input: 5, [1,2,5]
Expected: 4
#2 Impossible target amount
Input: 3, [2]
Expected: 0
#3 Single exact coin match
Input: 10, [10]
Expected: 1
JavaScript
Output
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