package main

import (
	"fmt"
	"math"
	"sort"
)

func main() {
	points := [][]int{{2, 1}, {2, 2}, {3, 3}}
	angle := 90
	location := []int{1, 1}
	ret := visiblePoints(points, angle, location)
	fmt.Println(ret)
}

func visiblePoints(points [][]int, angle int, location []int) int {
	n := len(points)
	a := location[0]
	b := location[1]
	zero := 0
	arr := make([]float64, n<<1)
	m := 0
	for i := 0; i < n; i++ {
		x := points[i][0] - a
		y := points[i][1] - b
		if x == 0 && y == 0 {
			zero++
		} else {
			math.Atan2(float64(y), float64(x))
			arr[m] = toDegrees(math.Atan2(float64(y), float64(x)))
			arr[m+1] = arr[m] + 360
			m += 2
		}
	}
	sort.Float64s(arr[0:m])
	max := 0
	for L, R := 0, 0; L < n; L++ {
		for R < m && arr[R]-arr[L] <= float64(angle) {
			R++
		}
		max = getMax(max, R-L)
	}
	return max + zero
}

func getMax(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func toDegrees(x float64) float64 {
	return x * (180.0 / math.Pi)
}