Recently I faced this question
Suppose here are a given array [1,5,12,20] and max=7
We need to making all the values from 1 to max
So find the smallest coins to make from all the value 1 to max
Here if I use 7 coins of 1 dollar we can easily make all the value from 1 to 7 -So 7 coins needed here
If I use 4 coins of 1 dollar and 1 coins of 5 dollar we can also make all the value from 1 to 7- Here 5 coins needed
So my smallest answer is 5 not 7

How can I solve this problem? Do you have any idea?