static void Main(string[] args)
{
MyTreeNode node1 = new MyTreeNode()
{
Data = 1
};
MyTreeNode node2 = new MyTreeNode()
{
Data = 2
};
MyTreeNode node3 = new MyTreeNode()
{
Data = 3
};
MyTreeNode node4 = new MyTreeNode()
{
Data = 4
};
MyTreeNode node5 = new MyTreeNode()
{
Data = 5
};
MyTreeNode node6 = new MyTreeNode()
{
Data = 6
};
node1.Left = node2;
node1.Right = node3;
node2.Left = node4;
node2.Right = node5;
node3.Right = node6;
MyTreeNode node7 = new MyTreeNode()
{
Data = 7
};
MyTreeNode parent = node1.FindNearestParent2(node1, node1);
Console.WriteLine(parent.Data);
//var paths = node1.FindAllPath();
//foreach(var p in paths)
//{
// foreach(var node in p)
// {
// Console.Write(node.Data + "-->");
// }
// Console.WriteLine( );
//}
}
/// <summary>
/// 判断当前树当中，是否包含目标节点
/// </summary>
/// <param name="root">树的根节点</param>
/// <param name="target">目标节点</param>
/// <returns>True - root 这棵树中包含target节点， false不包含</returns>
private static bool Contains(MyTreeNode root, MyTreeNode target)
{
if (root != null && target != null)
{
if (root == target)
{
return(true);
}
return(Contains(root.Left, target) || Contains(root.Right, target));
}
return(false);
}
public MyTreeNode FindNearestParent2(MyTreeNode first, MyTreeNode second)
{
List <List <MyTreeNode> > allPaths = this.FindAllPath();
List <MyTreeNode> firstPath = null;
List <MyTreeNode> secondPath = null;
for (int index = 0; index < allPaths.Count; index++)
{
for (int i = 0; i < allPaths[index].Count; i++)
{
if (allPaths[index][i] == first)
{
firstPath = allPaths[index];
}
if (allPaths[index][i] == second)
{
secondPath = allPaths[index];
}
}
}
MyTreeNode parent = null;
if (firstPath != null && firstPath.Count > 0 && secondPath != null && secondPath.Count > 0)
{
for (int index = 0; index < firstPath.Count && index < secondPath.Count; index++)
{
if (firstPath[index] != first && secondPath[index] != second)
{
parent = firstPath[index];
}
else
{
break;
}
}
}
return(parent);
}
public MyTreeNode FindNearestParent(MyTreeNode first, MyTreeNode second)
{
var leftContainsFirst = Contains(this.Left, first);
var rightContainsSecond = Contains(this.Right, second);
var leftContainsSecond = Contains(this.Left, second);
var rightContainsFirst = Contains(this.Right, first);
if ((leftContainsFirst && rightContainsSecond) || (leftContainsSecond && rightContainsFirst))
{
return(this);
}
else
{
if (leftContainsFirst && leftContainsSecond)
{
if (this.Left != null)
{
if (this.Left == first || this.Left == second)
{
return(this);
}
return(this.Left.FindNearestParent(first, second));
}
}
if (rightContainsFirst && rightContainsSecond)
{
if (this.Right != null)
{
if (this.Right == first || this.Right == second)
{
return(this);
}
return(this.Right.FindNearestParent(first, second));
}
}
}
return(null);
}