0469. Convex Polygon

https://leetcode.com/problems/convex-polygon

Description

You are given an array of points on the X-Y plane points where points[i] = [xi, yi]. The points form a polygon when joined sequentially.

Return true if this polygon is convex and false otherwise.

You may assume the polygon formed by given points is always a simple polygon. In other words, we ensure that exactly two edges intersect at each vertex and that edges otherwise don't intersect each other.

Example 1:

**Input:** points = [[0,0],[0,5],[5,5],[5,0]]
**Output:** true

Example 2:

**Input:** points = [[0,0],[0,10],[10,10],[10,0],[5,5]]
**Output:** false

Constraints:

• 3 <= points.length <= 104

• points[i].length == 2

• -104 <= xi, yi <= 104

• All the given points are unique.

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