Chef and Shops

In another universe Chef was a billionaire and he had $N$ shops in a line. Each shop is has a Business-value represented by array $A$ denoting the type of business in the $i$-th shop. There are in total $M$ business, means that each shop has an integer value between $1$ to $M$. Some shops have value $0$, that means Chef has not yet decided which business to set up in the shop and therefore these