using System;

//節點
public class LinkNode
{
   public int val;
   public LinkNode next;
   public LinkNode(int val,LinkNode next){
	   this.val = val;
	   this.next = next;
   }
   public LinkNode(int val){
	   this.val = val;
	   this.next = null;
   }
};

public class Program
{
	// SingleLinkList 串接節點
	public static void Main()
	{
	
		LinkNode node1 = new LinkNode(12); 
		LinkNode node2 = new LinkNode(99); 
		LinkNode node3 = new LinkNode(37); 
		
		node1.next = node2; // 綁定node1的尾端接node2
		node2.next = node3; // 綁定node2的尾端接node3
		
	
		Console.WriteLine("手動印出節點:");
		Console.WriteLine(node1.val); // 節點1
		Console.WriteLine(node1.next.val);// 節點2 (節點1的下1個元素)
		Console.WriteLine(node1.next.next.val);// 節點3 (節點1的下2個元素)
		if(node1.next.next.next == null){ //節點4，尾端沒串接任何資料為null
			Console.WriteLine("null");
		}
		
		Console.WriteLine("遍歷節點:");
		LinkNode currentNode = node1;
		while(currentNode != null){ // null表示為末端
			Console.WriteLine(currentNode.val);
			// 將當前節點指到下個節點
			currentNode = currentNode.next;
		}
		
		Console.WriteLine("在節點1末端添加一個數值38的節點:");
		
		LinkNode cursor = node1; 
		LinkNode newNode = new LinkNode(38);
		
		// 添加節點在最後面
		while(true){
			if(cursor.next == null){ 
				cursor.next = newNode; // 找到最尾端把null指派成新節點38
				break;
			}else{
				cursor = cursor.next; //不斷往下找節點
			}
		}
		
		Console.WriteLine(node1.next.next.next.val); //Q1:可取得38，這邊其實我有些不懂，是new參考的關係嗎，為什麼能夠改到node1?
	}
}

手動印出節點:
12
99
37
null
遍歷節點:
12
99
37
在節點1末端添加一個數值38的節點:
38

在C#廣義來說
基本型別 Struct (int,double,float,byte ...)  可看作 傳值
一般型別 Class (自訂Class ,SqlConnectio....)  可看作 傳址  更精確來說是傳Stack的值(指向Heap的記憶體位置)

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     public int val;
 *     public ListNode next;
 *     public ListNode(int val=0, ListNode next=null) {
 *         this.val = val;
 *         this.next = next;
 *     }
 * }
 */

public class Solution {
  
    public ListNode AddTwoNumbers(ListNode l1, ListNode l2) {
        ListNode currentL1=l1,currentL2=l2;
        ListNode resultListNode = new ListNode();
        ListNode resultList = resultListNode; // 為什麼可以儲存?
        Boolean isAddOne = false;
        while(true){
            int sum = 0;
            if(currentL1!= null){
                sum +=  currentL1.val;
                currentL1 = currentL1.next;
            }
            if(currentL2!= null){
              sum +=  currentL2.val;
              currentL2 = currentL2.next;
            }
            
            if(isAddOne){
                sum+=1;
            }
            
            if(sum >= 10){
                isAddOne = true;
                sum = sum%10; 
            }else{
                isAddOne = false;
            }
            
            resultListNode.next = new ListNode(sum); 
            resultListNode = resultListNode.next; // ?? 因C#傳址可影響到原本的resultList
            
            if(currentL1 == null && currentL2 == null && isAddOne == false){
                break;
            }
        }
        return resultList.next;
    }
}

public class Solution {
    public int[] TwoSum(int[] nums, int target) {
        for (int i = 0; i < nums.Length - 1 ; i++)
        {
            for(int j=i+1;j < nums.Length;j++){
                if(nums[i]+nums[j] == target){
                     return new int[] { i,j };
               }
            }
        }
        return new int[]{};
    }
}

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
      for (let i = 0; i < nums.length - 1 ; i++)
        {
            for(let j=i+1;j < nums.length;j++){
                if(nums[i]+nums[j] === target){
                     return [i,j];
               }
            }
        }
        return [];
};