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LeetCode 478. Generate Random Point in a Circle

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题目

原题在此

解析

线性的对半径取随机的话, 会导致origin附近的样本点比外围多, 使得样本分布不均匀, 要取sqrt().
延伸阅读

代码

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class Solution {
public:
    Solution(double radius, double x_center, double y_center): r{radius}, x{x_center}, y{y_center} {};
    vector<double> randPoint() {
        double theta = 2 * PI * ((double)rand() / RAND_MAX);
        double ran = sqrt(((double)rand() / RAND_MAX));
        double foo = x + ran * r * cos(theta), bar = y + ran * r * sin(theta);
        return {foo, bar};  
    }
    
private:
    double r, x, y;
    const double PI = 3.14159265358979323846;
};
    
    
 
/**
 * Your Solution object will be instantiated and called as such:
 * Solution* obj = new Solution(radius, x_center, y_center);
 * vector<double> param_1 = obj->randPoint();
 */