Hard

Quiz

#587 Erect the Fence

APPROACH

You are given an array trees where trees[i] = [xi, yi] represents the location of a tree in the garden.

Fence the entire garden using the minimum length of rope, as it is expensive. The garden is well-fenced only if all the trees are enclosed.

Return the coordinates of trees that are exactly located on the fence perimeter. You may return the answer in any order.

Example 1:

Input: trees = [[1,1],[2,2],[2,0],[2,4],[3,3],[4,2]]

Output: [[1,1],[2,0],[4,2],[3,3],[2,4]]

Explanation: All the trees will be on the perimeter of the fence except the tree at [2, 2], which will be inside the fence.

Example 2:

Input: trees = [[1,2],[2,2],[4,2]]

Output: [[4,2],[2,2],[1,2]]

Explanation: The fence forms a line that passes through all the trees.

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What is the optimal approach for this problem?