给出一个数组，一个数字，输出数组中所有两个元素相加正好等于该数字的组合，不能有重复。...

c# codes as below:

using System;

namespace MyApp

{

class Program

{

static void Main()

{

int[] arr1 = { -1, -2, 3, 4, -5, 6, 7, 8, 9, 4,4,4,4,4,4,4,4,4,4,10000,1,1,1,1,2,2,2,2,2,3,3,3,3,3,3,5,5,5,5,5,5,7,7,7,7,9,10,12,13};

int[] arr2 = { 0 };

int[] arr3 = new int[0];

GetNum(arr1, 8);

Console.WriteLine();

GetNum(arr2, 8);

Console.WriteLine();

GetNum(arr3, 8);

Console.ReadKey();

}

static void GetNum(int[] arr, int num)

{

if (arr.Length == 0 || arr == null)

return;

int maxNum = arr[0];

int minNum = arr[0];

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

{

if (maxNum < arr[i])

maxNum = arr[i];

if(minNum>arr[i])

minNum=arr[i];

}

bool[] marks = new bool[maxNum-minNum+1];

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

marks[arr[i] - minNum] = true;

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

{

if((num-arr[i]-minNum)>=0&&(num-arr[i]-minNum)<(maxNum-minNum))

{

if (marks[num - arr[i] - minNum] == true)

{

Console.WriteLine("{0} and {1}", arr[i], num - arr[i]);

marks[num - arr[i] - minNum] = false;

marks[arr[i] - minNum] = false;

}

}

}

}

}

}