478. Generate Random Point in a Circle.go

package leetcode

import (
"math"
"math/rand"
"time"
)

typeSolutionstruct {
rfloat64
xfloat64
yfloat64
}

funcConstructor(radiusfloat64, x_centerfloat64, y_centerfloat64) Solution {
rand.Seed(time.Now().UnixNano())
returnSolution{radius, x_center, y_center}
}

func (this*Solution) RandPoint() []float64 {
/*
 a := angle()
 r := this.r * math.Sqrt(rand.Float64())
 x := r * math.Cos(a) + this.x
 y := r * math.Sin(a) + this.y
 return []float64{x, y}*/
for {
rx:=2*rand.Float64() -1.0
ry:=2*rand.Float64() -1.0
x:=this.r*rx
y:=this.r*ry
ifx*x+y*y<=this.r*this.r {
return []float64{x+this.x, y+this.y}
 }
 }
}

funcangle() float64 {
returnrand.Float64() *2*math.Pi
}

/**
 * Your Solution object will be instantiated and called as such:
 * obj := Constructor(radius, x_center, y_center);
 * param_1 := obj.RandPoint();
 */