zoukankan      html  css  js  c++  java
  • LeetCode——Maximum Binary Tree

    Question

    Given an integer array with no duplicates. A maximum tree building on this array is defined as follow:

    The root is the maximum number in the array.
    The left subtree is the maximum tree constructed from left part subarray divided by the maximum number.
    The right subtree is the maximum tree constructed from right part subarray divided by the maximum number.
    Construct the maximum tree by the given array and output the root node of this tree.

    Example 1:
    Input: [3,2,1,6,0,5]
    Output: return the tree root node representing the following tree:

          6
        /   
       3     5
            / 
         2  0   
           
            1
    

    Note:
    The size of the given array will be in the range [1,1000].

    Solution

    递归求解。

    Code

    /**
     * Definition for a binary tree node.
     * struct TreeNode {
     *     int val;
     *     TreeNode *left;
     *     TreeNode *right;
     *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
     * };
     */
    class Solution {
    public:
        TreeNode* constructMaximumBinaryTree(vector<int>& nums) {
            struct TreeNode* root;
            return construct(root, nums, 0, nums.size() - 1);
        }
        TreeNode* construct(struct TreeNode* root, vector<int>& nums, int start, int end) {
            if (start > end) {
                return NULL;
            }
            int max_value = INT_MIN;
            int max_index = start;
            for (int i = start; i <= end; i++) {
                if (nums[i] > max_value) {
                    max_value = nums[i];
                    max_index = i;
                }
            }
            root = new TreeNode(max_value);
            root->left = construct(root, nums, start, max_index - 1);
            root->right = construct(root, nums, max_index + 1, end);
            
            return root;
        }
    };
    
  • 相关阅读:
    IOS开发——01_第一个OC程序
    01_iOS开发需要准备什么?
    正则表达式随笔
    .net4.6版本前设置window子窗口位置主窗口闪烁
    [CF1486D] Max Median
    [CF1487D] Pythagorean Triples
    [CF1487E] Cheap Dinner
    [CF1490E] Accidental Victory
    [CF1490F] Equalize the Array
    [CF1490G] Old Floppy Drive
  • 原文地址:https://www.cnblogs.com/zhonghuasong/p/7522709.html
Copyright © 2011-2022 走看看