Imagine that I have $1$ million dollars which I want to invest. I have a set of $N$ elements in which I can put the money and obtain a revenue. Each element has a function that determines how much money I have earn based on the invested money on that item.
For example: if I put $\$1000$, I get $\$1200$, if I put $\$2000$, I get $\$3000$.
With more money, there is always more return. Each element has its own different function.
So the question is what algorithm/strategy can I use to allocate the money in order to find the best return of investment?