package leetcode

func largestTriangleArea(points [][]int) float64 {
	maxArea, n := 0.0, len(points)
	for i := 0; i < n; i++ {
		for j := i + 1; j < n; j++ {
			for k := j + 1; k < n; k++ {
				maxArea = max(maxArea, area(points[i], points[j], points[k]))
			}
		}
	}
	return maxArea
}

func area(p1, p2, p3 []int) float64 {
	return abs(p1[0]*p2[1]+p2[0]*p3[1]+p3[0]*p1[1]-p1[0]*p3[1]-p2[0]*p1[1]-p3[0]*p2[1]) / 2
}

func abs(num int) float64 {
	if num < 0 {
		num = -num
	}
	return float64(num)
}

func max(a, b float64) float64 {
	if a > b {
		return a
	}
	return b
}