478. 在圆内随机生成点
给定圆的半径和圆心的位置，实现函数 randPoint ，在圆中产生均匀随机点。
实现 Solution 类:
Solution(double radius, double x_center, double y_center) 用圆的半径 radius 和圆心的位置 (x_center, y_center) 初始化对象randPoint() 返回圆内的一个随机点。圆周上的一点被认为在圆内。答案作为数组返回 [x, y] 。
示例 1：
输入: ["Solution","randPoint","randPoint","randPoint"] [[1.0, 0.0, 0.0], [], [], []] 输出: [null, [-0.02493, -0.38077], [0.82314, 0.38945], [0.36572, 0.17248]] 解释: Solution solution = new Solution(1.0, 0.0, 0.0); solution.randPoint ();//返回[-0.02493，-0.38077] solution.randPoint ();//返回[0.82314,0.38945] solution.randPoint ();//返回[0.36572,0.17248]
提示：
0 < radius <= 108-107 <= x_center, y_center <= 107randPoint 最多被调用 3 * 104 次相似题目
原站题解
python3 解法, 执行用时: 148 ms, 内存消耗: 25 MB, 提交时间: 2022-12-04 17:58:22
class Solution:
def __init__(self, radius: float, x_center: float, y_center: float):
self.xc = x_center
self.yc = y_center
self.r = radius
def randPoint(self) -> List[float]:
u, theta = random.random(), random.random() * 2 * math.pi
r = sqrt(u)
return [self.xc + r * math.cos(theta) * self.r, self.yc + r * math.sin(theta) * self.r]
# Your Solution object will be instantiated and called as such:
# obj = Solution(radius, x_center, y_center)
# param_1 = obj.randPoint()
javascript 解法, 执行用时: 136 ms, 内存消耗: 57.1 MB, 提交时间: 2022-12-04 17:57:56
/**
* @param {number} radius
* @param {number} x_center
* @param {number} y_center
*/
var Solution = function(radius, x_center, y_center) {
this.xc = x_center;
this.yc = y_center;
this.r = radius;
};
/**
* @return {number[]}
*/
Solution.prototype.randPoint = function() {
const u = Math.random();
const theta = Math.random() * 2 * Math.PI;
const r = Math.sqrt(u);
return [this.xc + r * Math.cos(theta) * this.r, this.yc + r * Math.sin(theta) * this.r];
};
/**
* Your Solution object will be instantiated and called as such:
* var obj = new Solution(radius, x_center, y_center)
* var param_1 = obj.randPoint()
*/
golang 解法, 执行用时: 40 ms, 内存消耗: 12.7 MB, 提交时间: 2022-12-04 17:57:31
type Solution struct {
radius, xCenter, yCenter float64
}
func Constructor(radius, xCenter, yCenter float64) Solution {
return Solution{radius, xCenter, yCenter}
}
func (s *Solution) RandPoint() []float64 {
r := math.Sqrt(rand.Float64())
sin, cos := math.Sincos(rand.Float64() * 2 * math.Pi)
return []float64{s.xCenter + r*cos*s.radius, s.yCenter + r*sin*s.radius}
}
/**
* Your Solution object will be instantiated and called as such:
* obj := Constructor(radius, x_center, y_center);
* param_1 := obj.RandPoint();
*/
java 解法, 执行用时: 230 ms, 内存消耗: 50.1 MB, 提交时间: 2022-12-04 17:57:16
class Solution {
Random random;
double xc, yc, r;
public Solution(double radius, double x_center, double y_center) {
random = new Random();
xc = x_center;
yc = y_center;
r = radius;
}
public double[] randPoint() {
double u = random.nextDouble();
double theta = random.nextDouble() * 2 * Math.PI;
double r = Math.sqrt(u);
return new double[]{xc + r * Math.cos(theta) * this.r, yc + r * Math.sin(theta) * this.r};
}
}
/**
* Your Solution object will be instantiated and called as such:
* Solution obj = new Solution(radius, x_center, y_center);
* double[] param_1 = obj.randPoint();
*/
java 解法, 执行用时: 213 ms, 内存消耗: 50.4 MB, 提交时间: 2022-12-04 17:56:43
class Solution {
Random random;
double xc, yc, r;
public Solution(double radius, double x_center, double y_center) {
random = new Random();
xc = x_center;
yc = y_center;
r = radius;
}
public double[] randPoint() {
while (true) {
double x = random.nextDouble() * (2 * r) - r;
double y = random.nextDouble() * (2 * r) - r;
if (x * x + y * y <= r * r) {
return new double[]{xc + x, yc + y};
}
}
}
}
/**
* Your Solution object will be instantiated and called as such:
* Solution obj = new Solution(radius, x_center, y_center);
* double[] param_1 = obj.randPoint();
*/
javascript 解法, 执行用时: 136 ms, 内存消耗: 57.2 MB, 提交时间: 2022-12-04 17:56:05
/**
* @param {number} radius
* @param {number} x_center
* @param {number} y_center
*/
var Solution = function(radius, x_center, y_center) {
this.xc = x_center;
this.yc = y_center;
this.r = radius;
};
/**
* @return {number[]}
*/
Solution.prototype.randPoint = function() {
while (true) {
const x = Math.random() * (2 * this.r) - this.r;
const y = Math.random() * (2 * this.r) - this.r;
if (x * x + y * y <= this.r * this.r) {
return [this.xc + x, this.yc + y];
}
}
};
/**
* Your Solution object will be instantiated and called as such:
* var obj = new Solution(radius, x_center, y_center)
* var param_1 = obj.randPoint()
*/
golang 解法, 执行用时: 44 ms, 内存消耗: 12.7 MB, 提交时间: 2022-12-04 17:55:12
type Solution struct {
radius, xCenter, yCenter float64
}
func Constructor(radius, xCenter, yCenter float64) Solution {
return Solution{radius, xCenter, yCenter}
}
func (s *Solution) RandPoint() []float64 {
for {
x := rand.Float64()*2 - 1
y := rand.Float64()*2 - 1 // [-1,1) 的随机数
if x*x+y*y < 1 {
return []float64{s.xCenter + x*s.radius, s.yCenter + y*s.radius}
}
}
}
/**
* Your Solution object will be instantiated and called as such:
* obj := Constructor(radius, x_center, y_center);
* param_1 := obj.RandPoint();
*/
python3 解法, 执行用时: 148 ms, 内存消耗: 24.7 MB, 提交时间: 2022-12-04 17:54:58
class Solution:
def __init__(self, radius: float, x_center: float, y_center: float):
self.xc = x_center
self.yc = y_center
self.r = radius
def randPoint(self) -> List[float]:
while True:
x, y = random.uniform(-self.r, self.r), random.uniform(-self.r, self.r)
if x * x + y * y <= self.r * self.r:
return [self.xc + x, self.yc + y]
# Your Solution object will be instantiated and called as such:
# obj = Solution(radius, x_center, y_center)
# param_1 = obj.randPoint()