Number of Pairs of Interchangeable Rectangles
You are given n rectangles represented by a 0-indexed 2D integer array rectangles, where rectangles[i] = [widthi, heighti] denotes the width and height of the i^th rectangle.
Two rectangles i and j (i < j) are considered interchangeable if they have the same width-to-height ratio. More formally, two rectangles are interchangeable if widthi / heighti == widthj / heightj using decimal division, not integer division.
Return the number of pairs of interchangeable rectangles in rectangles.
Example 1
Input
rectangles = [[4,8],[3,6],[10,20],[15,30]]Output
6All four rectangles have the same width-to-height ratio, so all six possible pairs are interchangeable.
Example 2
Input
rectangles = [[4,5],[7,8]]Output
0There are no interchangeable pairs of rectangles.
Constraints
- n == rectangles.length
- 1 <= n <= 10^5
- rectangles[i].length == 2
- 1 <= widthi, heighti <= 10^5