Given an integer n, return true if n has exactly three distinct positive divisors. Otherwise, return false. A divisor of n is a positive integer that divides n without leaving a remainder.
You are given a list of rectangles, each represented by its width and height. Two rectangles are interchangeable if their width-to-height ratios are the same. Your task is to return the number of interchangeable rectangle pairs in the list.
You are given a list of stock prices where each element represents the stock price on a specific day. The stock prices are given as pairs where the first element is the day number and the second element is the stock price for that day. A line chart can be drawn by plotting these prices on an XY-plane, where the X-axis represents the day and the Y-axis represents the price. Your task is to determine the minimum number of lines required to represent the stock prices as a continuous line chart.
You are given two positive integers, a and b. Your task is to find the number of common divisors (factors) between a and b. A number x is considered a common divisor of a and b if it divides both a and b without leaving any remainder.