LeetCode-in-Swift
322. Coin Change
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.
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
Example 3:
Input: coins = [1], amount = 0
Output: 0
Constraints:
1 <= coins.length <= 121 <= coins[i] <= 231 - 10 <= amount <= 104
Solution
class Solution {
func coinChange(_ coins: [Int], _ amount: Int) -> Int {
if amount < 1 { return 0 }
let dummyValue: Int = .max
var minCoinsHolder = Array(repeating: dummyValue, count: amount + 1)
minCoinsHolder[0] = 0
for intermediateAmount in 1 ... amount {
var minCoins = dummyValue
for coin in coins {
if intermediateAmount >= coin {
let reminder = intermediateAmount - coin
let minCoinsForReminder = minCoinsHolder[reminder]
if minCoinsForReminder == dummyValue { continue }
minCoins = min(minCoins, 1 + minCoinsForReminder)
}
}
minCoinsHolder[intermediateAmount] = minCoins
}
return minCoinsHolder[amount] == dummyValue ? -1 : minCoinsHolder[amount]
}
}