共同祖先

共同祖先

                   1
           2               3
    4         5        6        7
 N    N    8     9   N    N  10    11

1. 输入：int[] nums={1,2,3,4,5,6,7,N,N,8,9,N,N,10,11};
2. 代码：

class Ancestors
{
public class Trees
{
public int NodeTree { get; set; }//根节点
public int LeftTree { get; set; } //左节点
public int RightTree { get; set; }//右节点
public int Hierarchy { get; set; }//层级
}

    public void MainAncestors()
    {
        int[] nums = { 1, 2, 3, 4, 5, 6, 7, -2, -2, 8, 9, -2, -2, 10, 11 };

        List<Trees> listTree = new List<Trees>();
        listTree.Add(new Trees
        {
            NodeTree = 1,
            LeftTree = 2,
            RightTree = 3,
            Hierarchy = 0
        });

        listTree.Add(new Trees
        {
            NodeTree = 2,
            LeftTree = 4,
            RightTree = 5,
            Hierarchy = 1
        }) ;
        listTree.Add(new Trees
        {
            NodeTree = 3,
            LeftTree = 6,
            RightTree = 7,
            Hierarchy = 1
        });
        listTree.Add(new Trees
        {
            NodeTree = 4,
            LeftTree = -2,
            RightTree = -2,
            Hierarchy = 2
        });
        listTree.Add(new Trees
        {
            NodeTree = 5,
            LeftTree = 8,
            RightTree = 9,
            Hierarchy = 2
        });
        listTree.Add(new Trees
        {
            NodeTree = 6,
            LeftTree = -2,
            RightTree = -2,
            Hierarchy = 2
        });
        listTree.Add(new Trees
        {
            NodeTree = 7,
            LeftTree = 10,
            RightTree = 11,
            Hierarchy = 2
        });

        Trees LastTree = new Trees {
            NodeTree = -1,
            LeftTree = -1,
            RightTree = -1,
            Hierarchy = -1
        };

        List<Trees> LtreesValue = new List<Trees>();//左节点所涉及的集合
        List<Trees> RtreesValue = new List<Trees>();//右节点所涉及的集合
        int nums1 = Convert.ToInt32(Console.ReadLine());
        int nums2 = Convert.ToInt32(Console.ReadLine());
        DownLeftTrees(nums1, listTree, ref LtreesValue);//从上至下
       
        UpLeftTrees(nums1, listTree, ref LtreesValue);//从下至上（所涉及nums1的全部节点）

        DownLeftTrees(nums2, listTree, ref RtreesValue);
       
        UpLeftTrees(nums2, listTree, ref RtreesValue);//所涉及nums2的全部节点

        for (int i=0;i< LtreesValue.Count; i++)
        {
            for (int j = 0; j < RtreesValue.Count; j++)
            {
                if (LtreesValue[i] == RtreesValue[j])
                {
                    if (LastTree.Hierarchy < RtreesValue[j].Hierarchy)
                    {
                        LastTree = RtreesValue[j];
                    }
                }
            }
        }
        Console.WriteLine(LastTree.NodeTree);
    }

    private void UpLeftTrees(int leftnums, List<Trees> listTree, ref List<Trees> LtreesValue)
    {
        for (int i = 0; i < listTree.Count; i++)
        {
            int lefttree = listTree[i].LeftTree;
            int nodetrees = listTree[i].NodeTree;
            int righttree = listTree[i].RightTree;

            if (lefttree == leftnums || righttree == leftnums|| nodetrees == leftnums)
               //如果上层树中包含leftnums，LtreesValue++
            {
                if (!LtreesValue.Contains(listTree[i]))
                {
                    LtreesValue.Add(listTree[i]);
                    UpLeftTrees(nodetrees , listTree, ref LtreesValue);
                }
            }
        }
    }

    private void DownLeftTrees(int leftnums, List<Trees> listTree, ref List<Trees> LtreesValue)
    {
        for (int i = 0; i < listTree.Count; i++)
        {
            int lefttree = listTree[i].LeftTree;
            int nodetrees = listTree[i].NodeTree;
            int righttree = listTree[i].RightTree;

            if (nodetrees == leftnums)// 如果下层树中包含leftnums，LtreesValue++
            {
                if (!LtreesValue.Contains(listTree[i]))
                {
                    LtreesValue.Add(listTree[i]);
                    DownLeftTrees(lefttree, listTree, ref LtreesValue);//左数
                }
                if (!LtreesValue.Contains(listTree[i]))
                {
                    LtreesValue.Add(listTree[i]);
                    DownLeftTrees(righttsree, listTree, ref LtreesValue);//右数
                }
            }
        }
    }
}

标签：RightTree,LtreesValue,祖先,NodeTree,int,listTree,new,共同
来源： https://blog.csdn.net/m0_46446454/article/details/113844872