OJ1 Two Sum

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TwoSum
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] numbers = { 2, 7, 11, 15 };
            int target = 9;
            TwoSum2(numbers, target);
        }

        public static int[] TwoSum(int[] numbers, int target)
        {
            int[] result = new int[2];
            int start = 0;
            int end = numbers.Length - 1;
            while (start < end)
            {
                if (numbers[start] + numbers[end] == target)
                {
                    result[0] = start + 1;
                    result[1] = end + 1;
                    break;
                }
                if (numbers[start] + numbers[end] < target)
                {
                    start++;
                }
                else
                {
                    end--;
                }
            }
            if (result[0] == 0 && result[1] == 0)
            {
                throw new Exception("Didn‘t find result");
            }
            else
            {
                Console.WriteLine("index1=" + result[0] + ", index2=" + result[1]);
                return result;
            }
        }

        public static int[] TwoSum2(int[] numbers, int target)
        {
            int[] results = new int[2];
            Hashtable ht = new Hashtable();
            for (int i = 0; i < numbers.Length; i++)
            {
                ht.Add(numbers[i],i);
            }
            for (int i = 0; i < numbers.Length; i++)
            {
                if (ht[target - numbers[i]]!=null && (int)ht[target - numbers[i]]!=i)
                {
                    results[0] = i +1;
                    results[1] = (int)ht[target - numbers[i]] + 1;
                    break;
                }
            }
            if (results[0] == 0 && results[1] == 0)
            {
                throw new Exception("Didn‘t find result");
            }
            else
            {
                Console.WriteLine("index1=" + results[0] + ", index2=" + results[1]);
                return results;
            }
        }
    }
}