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Solution: Erect the Fence

Understand how to compute the convex hull of a set of points to build the shortest fence enclosing all trees. Explore the Monotone Chain algorithm to identify boundary points by sorting and orientation checks, and learn about its time and space complexity.

Statement

You are given an array of points, trees, where trees[i] = [xᵢ, yᵢ] represents the location of a tree on a 2D plane. Your goal is to enclose all the trees using the shortest possible length of rope, forming a fence around the garden. A garden is considered well-fenced if every tree lies inside or on the boundary of the fence (i.e., the fence forms the convex hullThis is the smallest convex shape, completely encloses a set of points. of all the points).

Return the coordinates of the trees that lie exactly on the fence perimeter. You can return the answer in any order.

Constraints:

  • 11 \leq trees.length 300\leq 300

  • trees[i].length == 22

  • 00 \leq xi, yi 100\leq ...