Submission #5911725

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Source Code Expand

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;
using static System.Console;
using static System.Math;

class Program
{
    static void Main(string[] args)
    {
        int N = ReadLineParseInt();
        KeyValuePair<long, long>[] pos = new KeyValuePair<long, long>[N];
        for(int i = 0; i < N; i++)
        {
            long[] xy = ReadLine().Split(' ').Select(long.Parse).ToArray();
            pos[i] = new KeyValuePair<long, long>(xy[0], xy[1]);
        }
        int ans = 0;
        for(int i = 0; i < N - 2; i++)
            for(int j = i + 1; j < N - 1; j++)
                for(int k = j + 1; k < N; k++)
                {
                    long x1 = pos[j].Key - pos[i].Key;
                    long y1 = pos[j].Value - pos[i].Value;
                    long x2 = pos[k].Key - pos[i].Key;
                    long y2 = pos[k].Value - pos[i].Value;
                    long v = Abs(x1 * y2 - y1 * x2);
                    if (v != 0 && v % 2 == 0)
                        ans++;
                }
        WriteLine(ans);
    }
    static int ReadLineParseInt() => int.Parse(ReadLine());
}

Submission Info

Judge Result