获取二叉树中最大左节点
原文:https://www . geesforgeks . org/get-maximum-left-node-二叉树/
给定一棵树，任务是在二叉树的唯一左边节点中找到最大值。 例:
Input :
7
/ \
6 5
/ \ / \
4 3 2 1
Output :
6
Input :
1
/ \
2 3
/ / \
4 5 6
\ / \
7 8 9
Output :
8
按顺序遍历，只对左节点应用条件，得到左节点的最大值。 我们试着用代码来理解。
C++
// CPP program to print maximum element
// in left node.
#include <bits/stdc++.h>
using namespace std;
// A Binary Tree Node
struct Node {
int data;
struct Node *left, *right;
};
// Get max of left element using
// Inorder traversal
int maxOfLeftElement(Node* root)
{
int res = INT_MIN;
if (root == NULL)
return res;
if (root->left != NULL)
res = root->left->data;
// Return maximum of three values
// 1) Recursive max in left subtree
// 2) Value in left node
// 3) Recursive max in right subtree
return max({ maxOfLeftElement(root->left),
res,
maxOfLeftElement(root->right) });
}
// Utility function to create a new tree node
Node* newNode(int data)
{
Node* temp = new Node;
temp->data = data;
temp->left = temp->right = NULL;
return temp;
}
// Driver program to test above functions
int main()
{
// Let us create binary tree shown in above diagram
Node* root = newNode(7);
root->left = newNode(6);
root->right = newNode(5);
root->left->left = newNode(4);
root->left->right = newNode(3);
root->right->left = newNode(2);
root->right->right = newNode(1);
/* 7
/ \
6 5
/ \ / \
4 3 2 1 */
cout << maxOfLeftElement(root);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to print maximum element
// in left node.
import java.util.*;
class GfG {
// A Binary Tree Node
static class Node {
int data;
Node left, right;
}
// Get max of left element using
// Inorder traversal
static int maxOfLeftElement(Node root)
{
int res = Integer.MIN_VALUE;
if (root == null)
return res;
if (root.left != null)
res = root.left.data;
// Return maximum of three values
// 1) Recursive max in left subtree
// 2) Value in left node
// 3) Recursive max in right subtree
return Math.max(maxOfLeftElement(root.left),
Math.max(res, maxOfLeftElement(root.right)));
}
// Utility function to create a new tree node
static Node newNode(int data)
{
Node temp = new Node();
temp.data = data;
temp.left = null;
temp.right = null;
return temp;
}
// Driver program to test above functions
public static void main(String[] args)
{
// Let us create binary tree shown in above diagram
Node root = newNode(7);
root.left = newNode(6);
root.right = newNode(5);
root.left.left = newNode(4);
root.left.right = newNode(3);
root.right.left = newNode(2);
root.right.right = newNode(1);
/* 7
/ \
6 5
/ \ / \
4 3 2 1 */
System.out.println(maxOfLeftElement(root));
}
}
Python 3
# Python program to prmaximum element
# in left node.
# Utility class to create a
# new tree node
class newNode:
def __init__(self, data):
self.data = data
self.left = self.right = None
# Get max of left element using
# Inorder traversal
def maxOfLeftElement(root):
res = -999999999999
if (root == None):
return res
if (root.left != None):
res = root.left.data
# Return maximum of three values
# 1) Recursive max in left subtree
# 2) Value in left node
# 3) Recursive max in right subtree
return max({ maxOfLeftElement(root.left), res,
maxOfLeftElement(root.right) })
# Driver Code
if __name__ == '__main__':
# Let us create binary tree shown
# in above diagram
root = newNode(7)
root.left = newNode(6)
root.right = newNode(5)
root.left.left = newNode(4)
root.left.right = newNode(3)
root.right.left = newNode(2)
root.right.right = newNode(1)
# 7
# / \
# 6 5
# / \ / \
# 4 3 2 1
print(maxOfLeftElement(root))
# This code is contributed by PranchalK
C
// C# program to print maximum element
// in left node.
using System;
class GfG
{
// A Binary Tree Node
class Node
{
public int data;
public Node left, right;
}
// Get max of left element using
// Inorder traversal
static int maxOfLeftElement(Node root)
{
int res = int.MinValue;
if (root == null)
return res;
if (root.left != null)
res = root.left.data;
// Return maximum of three values
// 1) Recursive max in left subtree
// 2) Value in left node
// 3) Recursive max in right subtree
return Math.Max(maxOfLeftElement(root.left),
Math.Max(res, maxOfLeftElement(root.right)));
}
// Utility function to create a new tree node
static Node newNode(int data)
{
Node temp = new Node();
temp.data = data;
temp.left = null;
temp.right = null;
return temp;
}
// Driver code
public static void Main(String[] args)
{
// Let us create binary tree
// shown in above diagram
Node root = newNode(7);
root.left = newNode(6);
root.right = newNode(5);
root.left.left = newNode(4);
root.left.right = newNode(3);
root.right.left = newNode(2);
root.right.right = newNode(1);
/* 7
/ \
6 5
/ \ / \
4 3 2 1 */
Console.WriteLine(maxOfLeftElement(root));
}
}
// This code is contributed by 29AjayKumar
java 描述语言
<script>
// JavaScript program to print maximum element
// in left node.
// A Binary Tree Node
class Node
{
constructor()
{
this.data = 0;
this.left = null;
this.right = null;
}
}
// Get max of left element using
// Inorder traversal
function maxOfLeftElement(root)
{
var res = -1000000000;
if (root == null)
return res;
if (root.left != null)
res = root.left.data;
// Return maximum of three values
// 1) Recursive max in left subtree
// 2) Value in left node
// 3) Recursive max in right subtree
return Math.max(maxOfLeftElement(root.left),
Math.max(res, maxOfLeftElement(root.right)));
}
// Utility function to create a new tree node
function newNode(data)
{
var temp = new Node();
temp.data = data;
temp.left = null;
temp.right = null;
return temp;
}
// Driver code
// Let us create binary tree
// shown in above diagram
var root = newNode(7);
root.left = newNode(6);
root.right = newNode(5);
root.left.left = newNode(4);
root.left.right = newNode(3);
root.right.left = newNode(2);
root.right.right = newNode(1);
/* 7
/ \
6 5
/ \ / \
4 3 2 1 */
document.write(maxOfLeftElement(root));
</script>
Output:
6
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