[TwoSum]05-04

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace Algorithm1
{
    public class App
    {
        private int[] arr = { 11, 19, 2, 7 };
 
        public App()
        {
 
        }
 
        public void Start()
        {
            //a의 각원소를 더해 9가 나오나 검사
            for (int i = 0; i < this.arr.Length; i++)
            {
                Console.WriteLine("index[{0}] : {1}", i, arr[i]);
            }
            Console.WriteLine();
 
            var arr2 = this.TwoSum(this.arr, 9);
            for (int i = 0; i < arr2.Length; i++)
            {
                Console.WriteLine("index : {0}", arr2[i]);
            }
 
            var arr3 = this.TwoSum2(this.arr, 9);
 
            for (int i = 0; i < arr3.Length; i++)
            {
                Console.WriteLine("index : {0}", arr3[i]);
            }
        }
 
        public int[] TwoSum(int[] nums, int target)
        {
            int[] returnArr = new int[2];
            for (int i = 0; i < nums.Length - 1; i++)
            {
                for (int j = 1; j < nums.Length; j++)
                {
                    if (nums[i] + nums[j] == target)
                    {
                        Console.WriteLine("index[{0}], index[{1}] = {2}", i, j, nums[i] + nums[j]);
                        returnArr[0] = i;
                        returnArr[1] = j;
                    }
                }
            }
            return returnArr;
        }
 
        public int[] TwoSum2(int[] nums, int target)
        {
            int[] returnAtrr = new int[2];
            int index = 0;
            for (int i = 0; i < nums.Length; i++)
            {
                Console.WriteLine("index[{0}] + index[{1}] : {2} ", index, i, nums[index] + nums[i]);
                if (nums[index] + nums[i] == target)
                {
                    returnAtrr[0] = index;
                    returnAtrr[1] = i;
                    break;
                }
 
                if (returnAtrr[0] == 0 && returnAtrr[1] == 0 && i == nums.Length-1)
                {
                    index++;
                    i = 0;
                }
            }
 
            return returnAtrr;
        }
    }
}