【leetcode】最大三角形面积

 /*遍历所有3个店组合可能，求3边，海伦公式求面积 sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a))/4 */

double largestTriangleArea(int** points, int pointsSize, int* pointsColSize){
    double area=0,a,b,c;
    for (int i=0; i<pointsSize-2; i++)
        for (int j=i+1; j<pointsSize-1; j++)
            for (int k=j+1; k<pointsSize; k++){
                a = sqrt(pow(abs(points[i][0] - points[j][0]),2) + pow(abs(points[i][1] - points[j][1]),2));
                b = sqrt(pow(abs(points[i][0] - points[k][0]),2) + pow(abs(points[i][1] - points[k][1]),2));
                c = sqrt(pow(abs(points[j][0] - points[k][0]),2) + pow(abs(points[j][1] - points[k][1]),2));
                area = (sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a))/4 > area)? sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a))/4: area;
            }
    return area;
}