using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("FindPairs\n");

        //var res = FindPairs(new int[]{-1,-2,-3}, 1);

        //var res = FindPairs(new int[]{3,1,4, 1, 5}, 2);

        //var res = FindPairs(new int[]{1,2,4,4,3,3,0,9,2,3}, 3);       

        //var res = FindPairs(new int[]{1,1,1,2,2}, 0);     

        //var res = FindPairs(new int[]{-1,0,0,1,0,0,-1}, 1);       

        //var res = FindPairs(new int[]{6, 3, 5, 7, 2, 3, 3, 8, 2, 4}, 2); // >> (5,3) (7,5) (8,6) (4,2) (6, 4)

        var res = FindPairs(new int[]{-1, -1, 1, 1}, 0);

        Console.WriteLine("result: ======================= >{0}", res);

    }

​

    public static int FindPairs(int[] nums, int k)

    {

        var x = new Dictionary<int, int>();

        int ret = 0;

        for (int i = 0; i < nums.Length; i++)

        {

            //Console.WriteLine("{0},{1}, k + nums[i]: {2}, nums[i] - k:{3}, x.ContainsKey(nums[i]):{4}\n", nums[i], x.ContainsKey(k + nums[i]) || x.ContainsKey(nums[i] - k), k + nums[i], nums[i] - k, x.ContainsKey(nums[i]));

            Console.WriteLine("******** {0},k + nums[i]: {1}, nums[i] - k: {2}, x.ContainsKey(k + nums[i]): {3}, x.ContainsKey(nums[i] - k): {4} \n\n ", nums[i], k + nums[i], nums[i] - k, x.ContainsKey(k + nums[i]), x.ContainsKey(nums[i] - k));

            Console.WriteLine("1)");

            //Console.WriteLine("x.ContainsKey(x[k + nums[i]]: {0}",    x.ContainsKey(x[k + nums[i]]));

            if (x.ContainsKey(k + nums[i]))

            {

                Console.WriteLine("x[k + nums[i]]: {0}", x[k + nums[i]]);

                if ((!x.ContainsKey(x[k + nums[i]]) || (x.ContainsKey(x[k + nums[i]]) && x[k + nums[i]] != nums[i])) && (!x.ContainsKey(nums[i]) || (x.ContainsKey(nums[i]) && x[nums[i]] != k + nums[i])))

                {

                    //Console.WriteLine("\nx.ContainsKey(x[k + nums[i]]): {0}, key:{1}, value:{2}\n", x.ContainsKey(x[k + nums[i]]), x[k + nums[i]], x[x[k + nums[i]]]);

                    ret++;

                    x[k + nums[i]] = nums[i];

                    Console.WriteLine("o~o");

                    Console.WriteLine("ret >>> {0}, !!!!! pair: (key:{1}, value:{2}) !!!!! ", ret, k + nums[i], nums[i]);

                    Console.WriteLine("o~o");

                }

            }

​

            Console.WriteLine("2)");

            if (x.ContainsKey(nums[i] - k))

            {

                if ((!x.ContainsKey(x[nums[i] - k]) || (x.ContainsKey(x[nums[i] - k]) && x[nums[i] - k] != nums[i])) && (!x.ContainsKey(nums[i]) || (x.ContainsKey(nums[i]) && x[nums[i]] != nums[i] - k)))

                {

                    ret++;

                    x[nums[i] - k] = nums[i];

                    Console.WriteLine("o~o");

                    Console.WriteLine("ret >>> {0}, !!!!! pair: (key:{1}, value:{2}) !!!!! ", ret, nums[i] - k, nums[i]);

                    Console.WriteLine("o~o");

                }

            }

​

            if (!x.ContainsKey(nums[i]))

            {

                x.Add(nums[i], int.MinValue);

            //Console.WriteLine("\noooooooooo>>>> Added: nums[i]:{0}\n\n", nums[i]);

            }

        }

​

        return ret;

    }

}