LeetCode-Solutions/C++/largest-triangle-area.cpp at master · madrobot/LeetCode-Solutions · GitHub

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// Time:  O(n^3)
// Space: O(1)

class Solution {
public:
    double largestTriangleArea(vector<vector<int>>& points) {
        double result = 0.0;
        for (int i = 0; i < points.size() - 2; ++i) {
            for (int j = i + 1; j < points.size() - 1; ++j) {
                for (int k = j + 1; k < points.size(); ++k) {
                    result = max(result,
                                 0.5 * abs(points[i][0] * points[j][1] +
                                           points[j][0] * points[k][1] +
                                           points[k][0] * points[i][1] -
                                           points[j][0] * points[i][1] -
                                           points[k][0] * points[j][1] -
                                           points[i][0] * points[k][1]));
                }
            }
        }
        return result;
    }
};