Closest Pair of Points

Given a list of points [x, y], return the minimum squared Euclidean distance between any two distinct points.

Function signature

func ClosestPairDistance(points [][]int) int64

Example

points = [[0,0],[3,4],[7,7],[1,1]]
output = 2

Constraints

• 0 <= len(points) <= 200_000
• -1_000_000_000 <= x, y <= 1_000_000_000

Notes

• Use divide-and-conquer in O(n log n).
• Return squared distance to avoid floating point.