QUESTION:

A boomerang is a set of 3 points that are all distinct and not in a straight line.

Given a list of three points in the plane, return whether these points are a boomerang.

Example 1:

Input: [[1,1],[2,3],[3,2]] Output: true Example 2:

Input: [[1,1],[2,2],[3,3]] Output: false

Note:

points.length == 3 points[i].length == 2 0 <= points[i][j] <= 100

EXPLANATION:

这个题目有两个想法 1.可以通过两个点计算出ax+b=y,然后再将最后一个点带入 2.既然三个点一个直线，那么就说明他们中两个点的距离等于第三个点的距离 所以我们采用的是第二个方法。 1.传入两两的点来计算距离 2.判断是否有两段距离相加等于第三段距离

SOLUTION:

class Solution {
    public boolean isBoomerang(int[][] points) {
       double disA = isBoomerangHelper(points[0],points[1]);
        double disB = isBoomerangHelper(points[1],points[2]);
        double disC = isBoomerangHelper(points[0],points[2]);
        return !(disA+disB==disC||disA+disC==disB||disB+disC==disA); 
    }
    
    
    public static double isBoomerangHelper(int[] A,int[] B){
        return Math.sqrt((A[0]-B[0])*(A[0]-B[0])+(A[1]-B[1])*(A[1]-B[1]));
    }
}