Example #1
0
        static void Main(string[] args)
        {
            var N  = int.Parse(Console.ReadLine());
            var ab = new double[N, 2];

            for (int i = 0; i < N; i++)
            {
                var read = Array.ConvertAll(Console.ReadLine().Split(' '), double.Parse);
                ab[i, 0] = read[0];
                ab[i, 1] = read[1];
            }
            long MOD = 1000000007;

            var ratio = new ElementCounter <double>();

            for (int i = 0; i < N; i++)
            {
                ratio.Add((double)ab[i, 0] / (double)ab[i, 1]);
            }
            long result = 0;

            for (int i = 0; i < N; i++)
            {
                result += modPow(2, N - ratio[-1 * (double)ab[i, 1] / (double)ab[i, 0]] - i - 1, MOD);
                result %= MOD;
                ratio.Remove((double)ab[i, 0] / (double)ab[i, 1]);
            }
            Console.WriteLine(result - 1);
        }
Example #2
0
        static void Main(string[] args)
        {
            var  N        = int.Parse(Console.ReadLine());
            var  A        = Array.ConvertAll(Console.ReadLine().Split(' '), long.Parse);
            var  reverseA = A.Reverse().ToArray();
            long result   = 0;

            for (int i = 0; i < N; i++)
            {
                A[i] = A[i] - i;
            }
            var counter1 = new ElementCounter <long>();

            foreach (long a in A)
            {
                counter1.Add(a);
            }
            foreach (long k in counter1.Dic.Keys)
            {
                if (k <= 0)
                {
                    continue;
                }
                if (counter1.Dic.ContainsKey(-k))
                {
                    result += counter1.Dic[k] * counter1.Dic[-k];
                }
            }
            for (int i = 0; i < N; i++)
            {
                reverseA[i] = reverseA[i] - i;
            }
            var counter2 = new ElementCounter <long>();

            foreach (long a in reverseA)
            {
                counter2.Add(a);
            }
            foreach (long k in counter2.Dic.Keys)
            {
                if (k <= 0)
                {
                    continue;
                }
                if (counter2.Dic.ContainsKey(-k))
                {
                    result += counter2.Dic[k] * counter2.Dic[-k];
                }
            }
            Console.WriteLine(result);
        }