Given coin denominations and a target amount, return the fewest coins needed. Return -1 if not possible.
Example:
Input:
1,2,5
11
Output:
3
Reasoning:
The target amount is 11 and the available coin denominations are 1, 2, and 5.
To find the fewest coins needed, we can use a combination of the largest denomination (5) and smaller denominations to reach the target amount: 5+5+1=11.
This combination requires 3 coins, which is the fewest number of coins needed to reach the target amount.
Therefore, the output is 3, indicating that 11 can be made with 3 coins.