Minimizing Coins

[dahiya-code]

Consider a money system consisting of n coins. 
Each coin has a positive integer value. 
Your task is to produce a sum of money x 
using the available coins in such a way that the 
number of coins is minimal.

For example, 
if the coins are {1,5,7} and the desired sum is 11, 
an optimal solution is 5+5+1 which requires 3 coins.

C++ DP soln

[dahiya-code]

Closes #228