Each entry [width, height] in rectangles describes one rectangle. Count index pairs i < j whose width-to-height ratios are exactly equal. Dimensions may differ as long as the ratios match. Width and height keep their roles, so rotating a rectangle is not allowed; identical entries at different indices still form separate pairs. Return the total number of matching pairs.
Example 1:
Input: rectangles = [[2,3],[4,6],[6,9]]
Output: 3Explanation: All three rectangles have ratio 2/3. The index pairs (0,1), (0,2), and (1,2) match, giving 3.
Example 2:
Input: rectangles = [[2,3],[3,2]]
Output: 0Explanation: The ratios 2/3 and 3/2 differ. Rotation is not allowed, so there are no matching pairs.
Example 3:
Input: rectangles = [[5,5],[5,5],[2,2],[2,3]]
Output: 3Explanation: The first three entries are squares and each pair among them matches, giving 3 pairs. The last rectangle has a different ratio.
Constraints:
1 <= rectangles.length <= 100000- Each rectangle has exactly two entries:
[width, height]. 1 <= width, height <= 100000