478. Generate Random Point in a Circle

题目

Given the radius and x-y positions of the center of a circle, write a function randPoint which generates a uniform randompoint in the circle.

Note:

1. input and output values are in floating-point.
2. radius and x-y position of the center of the circle is passed into the class constructor.
3. a point on the circumference of the circle is considered to bein the circle.
4. randPointreturnsa size 2 array containing x-position and y-position of the random point, in that order.

Example 1:

Input:
["Solution","randPoint","randPoint","randPoint"]
[[1,0,0],[],[],[]]
Output: [null,[-0.72939,-0.65505],[-0.78502,-0.28626],[-0.83119,-0.19803]]

Example 2:

Input:
["Solution","randPoint","randPoint","randPoint"]
[[10,5,-7.5],[],[],[]]
Output: [null,[11.52438,-8.33273],[2.46992,-16.21705],[11.13430,-12.42337]]

Explanation of Input Syntax:

The input is two lists:the subroutines calledand theirarguments.Solution'sconstructor has three arguments, the radius, x-position of the center, and y-position of the center of the circle. randPoint has no arguments.Argumentsarealways wrapped with a list, even if there aren't any.

解题思路

见程序注释