JavaScript Interview Prep:

Prompt

A teacher asks the class to open their books to a page number. A student can either start turning pages from the front of the book or from the back of the book. They always turn pages one at a time. When they open the book, page 1 is always on the right side.

Solution

//int n = number of pages in the book
//int p = the page number to flip to
function pageCount(n, p) {
    const fromFront = Math.floor(p/2);
    let fromBack = 0;
    
    if (n%2 == 0 && p%2 !== 0){
        fromBack = Math.floor((n-p)/2)+1;
    } else {
        fromBack = Math.floor((n-p)/2);
    }
    
    if (fromFront < fromBack){
        return fromFront;
    } else {
        return fromBack;
    }
}