public static Star findMajority(List <Star> A, long d)
{
if (A.Count == 0)
{
return(null);
}
else if (A.Count == 1)
{
return(A.ElementAt(0));
}
else
{
// Split into halves and recursively solve them
List <Star> firstHalf = new List <Star>();
for (int i = 0; i < A.Count / 2; i++)
{
firstHalf.Add(A.ElementAt(i));
}
List <Star> secondHalf = new List <Star>();
for (int i = A.Count / 2; i < A.Count; i++)
{
secondHalf.Add(A.ElementAt(i));
}
Star x = findMajority(firstHalf, d);
Star y = findMajority(secondHalf, d);
if (x == null && y == null)
{
return(null);
}
else if (x == null)
{
// count occurences of y in A, return y or NO
int count = 0;
foreach (Star s2 in A)
{
if (distanceBetweenStars(y, s2, d))
{
count++;
}
}
if (count > A.Count / 2)
{
return(y);
}
else
{
return(null);
}
}
else if (y == null)
{
// count occurences of x in A, return x or NO
int count = 0;
foreach (Star s2 in A)
{
if (distanceBetweenStars(x, s2, d))
{
count++;
}
}
if (count > A.Count / 2)
{
return(x);
}
else
{
return(null);
}
}
else
{
// count occurrences of x and y in A, return x, y, or NO
int ycount = 0;
int xcount = 0;
foreach (Star s2 in A)
{
if (distanceBetweenStars(y, s2, d))
{
ycount++;
}
if (distanceBetweenStars(x, s2, d))
{
xcount++;
}
}
if (xcount > A.Count / 2)
{
return(x);
}
else if (ycount > A.Count / 2)
{
return(y);
}
else
{
return(null);
}
}
}
}
/**
* Return true if s1 and s2 are with d of each other, false otherwise
**/
public static bool distanceBetweenStars(Star s1, Star s2, long d)
{
return((((s1.x - s2.x) * (s1.x - s2.x)) + ((s1.y - s2.y) * (s1.y - s2.y))) <= (d * d));
}
// not working correctly
public static Star findMajorityFaster(List <Star> A, long d)
{
if (A.Count == 0)
{
return(null);
}
else if (A.Count == 1)
{
return(A.ElementAt(0));
}
else
{
List <Star> APrime = new List <Star>();
Star y = null;
// Find A' and y
for (int i = 0; i < A.Count; i++)
{
if (i + 1 < A.Count)
{
Star s1 = A.ElementAt(i);
Star s2 = A.ElementAt(i + 1);
if (distanceBetweenStars(s1, s2, d))
{
APrime.Add(s1); // if the elements are are same, keep 1 of them in APrime
}
}
else
{
y = A.ElementAt(i); // if there's a leftover
}
}
Star x = findMajorityFaster(APrime, d);
if (x == null)
{
// if A is odd, count occurrences of y in A, return y or NO as appropriate
if (A.Count % 2 != 0)
{
// count occurences of y in A, return y or NO
int count = 0;
foreach (Star s2 in A)
{
if (distanceBetweenStars(y, s2, d))
{
count++;
}
}
if (count > A.Count / 2)
{
return(y);
}
else
{
return(null);
}
}
else
{
return(null); // else return NO
}
}
else
{
// count occurences of x in A, return x or NO
int count = 0;
foreach (Star s2 in A)
{
if (distanceBetweenStars(x, s2, d))
{
count++;
}
}
if (count > A.Count / 2)
{
return(x);
}
else
{
return(null);
}
}
}
}
static void Main(string[] args)
{
List <Star> allStars = new List <Star>();
Dictionary <long, long> stars = new Dictionary <long, long>();
long d = 0;
int count = 0;
string line;
string[] testingData = new string[8];
testingData[0] = "20 7";
testingData[1] = "1 1";
testingData[2] = "100 100";
testingData[3] = "1 3";
testingData[4] = "101 101";
testingData[5] = "3 1";
testingData[6] = "102 102";
testingData[7] = "3 3";
//string[] testingData = new string[5];
//testingData[0] = "10 4";
//testingData[1] = "45 46";
//testingData[2] = "90 47";
//testingData[3] = "45 54";
//testingData[4] = "90 43";
while ((line = Console.ReadLine()) != null)
//for (int i = 0; i < testingData.Length; i++)
{
string[] xy = line.Split(null);
//string[] xy = testingData.ElementAt(i).Split(null);
if (count == 0)
{
long.TryParse(xy[0], out d); // get the diameter
}
else
{
long x;
long y;
long.TryParse(xy[0], out x);
long.TryParse(xy[1], out y);
//stars.Add(x, y);
allStars.Add(new Star(x, y));
}
count++;
}
Star s1 = findMajority(allStars, d);
int total = 0;
if (s1 == null)
{
Console.WriteLine("NO");
}
else
{
foreach (Star s2 in allStars)
{
if (distanceBetweenStars(s1, s2, d))
{
total++;
}
}
}
if (total != 0)
{
Console.WriteLine(total);
}
//Console.ReadLine();
}
private Star findMajority(List <Star> stars)
{
if (stars.Count == 0)
{
return(null);
}
else if (stars.Count == 1)
{
return(stars[0]);
}
else
{
int i = 0;
List <Star> starsPrime = new List <Star>();
bool isOdd = false;
while (i <= stars.Count)
{
if (k % 2 != 0)
{
yStar = stars[stars.Count - 1];
//stars.Remove(stars[stars.Count - 1]);
isOdd = true;
}
if ((i + 1) >= stars.Count)
{
break;
}
long x1 = stars[i].x;
long y1 = stars[i].y;
long x2 = stars[i + 1].x;
long y2 = stars[i + 1].y;
if ((((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2))) <= d * d)
{
starsPrime.Add(stars[i]);
//stars.Remove(stars[i + 1]);
}
else
{
//stars.Remove(stars[i]);
//stars.Remove(stars[i + 1]);
}
i = i + 2;
}
xStar = findMajority(starsPrime);
if (xStar == null)
{
if (k % 2 != 0)
{
//int yStarCount = 0;
for (int j = 0; j < stars.Count; j++)
{
long x1 = yStar.x;
long y1 = yStar.y;
long x2 = stars[j].x;
long y2 = stars[j].y;
if ((((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2))) <= d * d)
{
yStarCount++;
}
}
if (yStarCount > stars.Count / 2)
{
return(yStar);
}
else
{
return(null);
}
}
else
{
return(null);
}
}
else
{
for (int j = 0; j < stars.Count; j++)
{
long x1 = xStar.x;
long y1 = xStar.y;
long x2 = stars[j].x;
long y2 = stars[j].y;
if ((((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2))) <= d * d)
{
xStarCount++;
}
}
if (xStarCount > stars.Count / 2)
{
return(xStar);
}
else
{
return(null);
}
}
}
}
private static void Main(string[] args)
{
GalaxyQuest gq = new GalaxyQuest();
string line;
string[] test = { "10 4", "45 46", "90 47", "45 54", "90 43" };
string[] test2 = { "20 7", "1 1", "100 100", "1 3", "101 101", "3 1", "102 102", "3 3" };
string[] test4 = { "20 9", "100 100", "1 1", "1 3", "101 101", "2 1", "3 1", "102 102", "3 3", "5000 3000" };
string[] test3 = { "20 6", "100 100", "1 1", "1 3", "3 1", "3 3", "101 101" };
string[] test5 = { "10 2", "1 1", "20 20" };
string[] test6 = { "10 6", "1 1", "20 20", "2 2", "3 3", "50 50", "70 70" };
string[] test7 = { "10 1", "1 1" };
string[] test8 = { "20 7", "100 100", "1 1", "1 3", "1010 1010", "2 1", "10200 10200", "3 3" };
int count = 1;
List <Star> stars = new List <Star>();
while ((line = Console.ReadLine()) != null)
//for(int l = 0; l < test5.Length; l++)
{
String[] splitLine = line.Split(null);
//String[] splitLine = test5[l].Split(null);
if (count != 1)
{
stars.Add(new Star(long.Parse(splitLine[0]), long.Parse(splitLine[1])));
}
else
{
gq.d = long.Parse(splitLine[0]);
gq.k = long.Parse(splitLine[1]);
}
count++;
}
Star answer = gq.findMajority(stars);
if (answer == stars[0])
{
Console.WriteLine(1);
}
else if (answer == null)
{
Console.WriteLine("NO");
}
else if (answer == gq.xStar)
{
Console.WriteLine(gq.xStarCount);
}
else
{
Console.WriteLine(gq.yStarCount);
}
//Console.Read();
}