Go: package main

import (
	"bufio"
	"os"
	"math"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

const (
	INF = 0x7FFFFFFF
	EPS = 1e-10
)

type Point struct {
	x, y float64
}
func (p *Point) plus(q *Point) *Point {
	return &Point{p.x + q.x, p.y + q.y}
}
func (p *Point) minus(q *Point) *Point {
	return &Point{p.x - q.x, p.y - q.y}
}
func (p *Point) multi(a float64) *Point {
	return &Point{p.x * a, p.y * a}
}
func (p *Point) div(a float64) *Point {
	return &Point{p.x / a, p.y / a}
}
func (p *Point) abs() float64 {
	return math.Sqrt(p.norm())
}
func (p *Point) norm() float64 {
	return p.x*p.x + p.y*p.y
}
func (p *Point) isLessThan(q *Point) bool {
	if p.x != q.x {
		return p.x < q.x && p.y < q.y
	}
	return true
}
func (p *Point) isEqual(q *Point) bool {
	return math.Abs(p.x - q.x) < EPS && math.Abs(p.y - q.y) < EPS
}

type Segment struct {
	p1, p2 *Point
}
func (s *Segment) norm() float64 {
	return (s.p2.x - s.p1.x)*(s.p2.x - s.p1.x) +
		(s.p2.y - s.p1.y)*(s.p2.y - s.p1.y)
}
func (s *Segment) abs() float64 {
	return math.Sqrt(s.norm())
}

func norm(a *Point) float64 {
	return a.x*a.x + a.y*a.y
}

func abs(a *Point) float64 {
	return math.Sqrt(norm(a))
}

func polar(a, r float64) *Point {
	return &Point{math.Cos(r)*a, math.Sin(r)*a}
}

func getDistance(a, b *Point) float64 {
	return abs(a.minus(b))
}

func dot(a, b *Point) float64 {
	return a.x*b.x + a.y*b.y
}

func cross(a, b *Point) float64 {
	return a.x*b.y - a.y*b.x
}

func getDistanceLP(s Segment, p *Point) float64 {
	return cross(s.p2.minus(s.p1), p.minus(s.p1))/ abs(s.p2.minus(s.p1))
}

func getDistanceSP(s Segment, p *Point) float64 {
	if dot(s.p2.minus(s.p1), p.minus(s.p1)) < 0 {
		return abs(p.minus(s.p1))
	}
	if dot(s.p1.minus(s.p2), p.minus(s.p2)) < 0 {
		return abs(p.minus(s.p2))
	}
	return getDistanceLP(s, p)
}

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		R, _ := strconv.Atoi(buf[0])
		N, _ := strconv.Atoi(buf[1])
		if R == 0 && N == 0 {
			break
		}
		p := make([]*Point, N)
		r := make([]float64, N)
		v := make([]float64, N)
		d := make([]float64, N)
		nd := make([]float64, N)
		die := make([]bool, N)
		for i := 0; i < N; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			_x, _ := strconv.ParseFloat(buf_[0], 64)
			_y, _ := strconv.ParseFloat(buf_[1], 64)
			_r, _ := strconv.ParseFloat(buf_[2], 64)
			_v, _ := strconv.ParseFloat(buf_[3], 64)
			tmp := &Point{_x, _y}
			p[i] = tmp
			r[i] = _r
			v[i] = _v
			nd[i] = getDistance(p[i], &Point{0, 0})
			d[i] = getDistance(p[i], &Point{0, 0})
			die[i] = false
		}
		for {
			for i := 0; i < N; i++ {
				nd[i] = math.Max(float64(R), nd[i]-v[i])
			}
			mini := float64(INF)
			id := -1
			for i := 0; i < N; i++ {
				if die[i] {
					continue
				}
				if nd[i] < EPS+float64(R) {
					continue
				}
				if nd[i] > mini {
					continue
				}
				mini = nd[i]
				id = i
			}
			if id == -1 {
				break
			}
			s := Segment{p[id], p[id]}
			s.p1 = s.p1.div(d[id])
			s.p1 = s.p1.multi(float64(R))
			s.p2 = s.p2.div(d[id])
			s.p2 = s.p2.multi(10000000.0)
			for i := 0; i < N; i++ {
				if nd[i] < EPS + float64(R) {
					continue
				}
				a := p[i]
				a = a.div(d[i])
				a = a.multi(nd[i])
				if getDistanceSP(s, a) < EPS + r[i] {
					die[i] = true
				}
			}
		}
		ans := 0
		for i := 0; i < N; i++ {
			if !die[i] {
				ans++
			}
		}
		fmt.Println(ans)
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <iomanip>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <bitset>
#include <stack>
#include <utility>
#include <numeric>
#include <algorithm>
#include <functional>
#include <cctype>
#include <complex>
#include <string>
#include <cstring>
#include <sstream>

using namespace std;

#define all(c) c.begin(),c.end()
#define rep(i,n) for(int i=0;i<(int)n;i++)

typedef long long ll;
typedef complex<double> point;
typedef pair<int,int> pii;

// →↑←↓
const int dx[] = {1,0,-1,0};
const int dy[] = {0,-1,0,1};

const double EPS = 1e-9;

struct ufo{
    point c;
    double r,v;
    bool alive;
};

//when goal return true;
bool go(ufo &u,int R){
    if(not u.alive) return false;
    if(abs(u.c) < R + u.v + EPS){
        u.c = 0;
        u.alive = false;
        return true;
    }else{
        u.c -= u.v * (u.c / (abs(u.c)));
        return false;
    }
}

double cross(point a,point b){
    return imag(conj(a)*b);
}

double dot(point a,point b){
    return real(conj(a)*b);
}
// 直線と点との距離
double dist_line_and_point(point a1,point a2,point b){
    return abs(cross(a2-a1,b-a1)) / abs(a2-a1);
}

// 線分と点との距離
double dist_linesegment_and_point(point a1,point a2,point b){
    if(dot(a2-a1,b-a1) < EPS) return abs(b-a1);
    if(dot(a1-a2,b-a2) < EPS) return abs(b-a2);
    return dist_line_and_point(a1,a2,b);
}

// 円と線分の交差判定
bool is_cross_linesegment_and_circle(point c,double r,point a1,point a2){
    return (dist_linesegment_and_point(a1,a2,c) < r+EPS and
             (r < abs(c-a1) + EPS or r < abs(c-a2) + EPS));
}

int main(){
    while(true){
        double R;
        int N;
        cin >> R >> N;
        if(abs(R) < EPS and N == 0) break;
        vector<ufo> us(N);

        for(int i=0;i<N;i++){
            cin >> us[i].c.real() >> us[i].c.imag() >> us[i].r >> us[i].v;
            us[i].alive = true;
        }

        int cnt = 0;
        while(true){
            int ac = 0;
            for(int i=0;i<N;i++){
                if(go(us[i],R)){
                    cnt++;
                }
                if(us[i].alive) ac++;
            }
            if(ac == 0) break;

            int nearest = 0;
            double mindist = 1e10;
            for(int i=0;i<N;i++){
                if(not us[i].alive) continue;
                if(mindist + EPS > abs(us[i].c)){
                    mindist = abs(us[i].c);
                    nearest = i;
                }
            }
            for(int i=0;i<N;i++){
                if(not us[i].alive) continue;
                if(is_cross_linesegment_and_circle(us[i].c,us[i].r,
                   us[nearest].c*point(1e10,0),us[nearest].c/abs(us[nearest].c)*R)){
                    us[i].alive = false;
                }
            }
        }
        cout << cnt << endl;

    }
    return 0;
}

C++: #include <algorithm>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <string>
#include <vector>

using namespace std;

#define reps(i,f,n) for(int i=f; i<int(n); ++i)
#define rep(i,n) reps(i,0,n)

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

const long double EPS = 1e-15;
const int INF = 1001001001;

struct UFO
{
	int r, v;
	long double a, arg;
	bool alive;
	UFO() : alive(true) {}
};

long double func(long double arg)
{
	if(arg <= -M_PI)
		arg += M_PI;
	if(arg > M_PI)
		arg -= M_PI;
	return arg;
}

int main()
{
	int R, n;
	while(scanf("%d%d", &R, &n), R){
		UFO ufo[100];
		rep(i, n){
			int x0, y0;
			scanf("%d%d%d%d", &x0, &y0, &ufo[i].r, &ufo[i].v);
			ufo[i].a = hypot((long double)x0, y0);
			ufo[i].arg = atan2((long double)y0, x0);
		}
		
		int cnt = 0;
		for(;;){
			int nearest = -1;
			rep(i, n){
				if(ufo[i].alive){
					ufo[i].a -= ufo[i].v;
					if(ufo[i].a < R+EPS){
						ufo[i].alive = false;
						++cnt;
					}
					else if(nearest==-1 || ufo[nearest].a > ufo[i].a)
						nearest = i;
				}
			}
			if(nearest == -1)
				break;

			long double arg = ufo[nearest].arg;
			rep(i, n){
				if(!ufo[i].alive)
					continue;
				if(ufo[i].r+EPS > ufo[i].a)
					ufo[i].alive = false;
				else{
					long double d = ufo[i].a*sin(arg - ufo[i].arg);
					if(abs(d) < ufo[i].r+EPS)
						ufo[i].alive = false;
				}
			}
		}
		printf("%d\n", cnt);
	}
	return 0;
}