Largest Triangle Area.py

'''

You have a list of points in the plane. Return the area of the largest triangle that can be formed by any 3 of the points.

Example:
Input: points = [[0,0],[0,1],[1,0],[0,2],[2,0]]
Output: 2
Explanation: 
The five points are show in the figure below. The red triangle is the largest.


Notes:

3 <= points.length <= 50.
No points will be duplicated.
 -50 <= points[i][j] <= 50.
Answers within 10^-6 of the true value will be accepted as correct.
'''

class Solution(object):
    def largestTriangleArea(self, points):
        """
        :type points: List[List[int]]
        :rtype: float
        """
        
        res = 0
        for i in xrange(len(points)):
            for j in xrange(i+1, len(points)):
                for k in xrange(j+1, len(points)):
                    res = max(res, self.getArea(points[i][0], points[i][1], points[j][0], points[j][1], points[k][0], points[k][1]))
        return res
    
    def getArea(self, x1, y1, x2, y2, x3, y3):
        return abs(x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2)) / 2.0