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Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level). Example 1: Input: 阅读全文
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Given the root of a binary tree, return the postorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [3,2,1] Example 2: 阅读全文
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Given the root of a binary tree, return the inorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [1,3,2] Example 2: I 阅读全文
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Given the root of a binary tree, invert the tree, and return its root. Example 1: Input: root = [4,2,7,1,3,6,9] Output: [4,7,2,9,6,3,1] Example 2: Inp 阅读全文
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Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center). Example 1: Input: root = [1,2,2,3,4,4,3] 阅读全文
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Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they a 阅读全文
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Given the root of a binary tree, return its maximum depth. A binary tree's maximum depth is the number of nodes along the longest path from the root n 阅读全文
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Given an unsorted array nums, reorder it in-place such that nums[0] <= nums[1] >= nums[2] <= nums[3].... Example: Input: nums = [3,5,2,1,6,4] Output: 阅读全文
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Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Exampl 阅读全文
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Reverse bits of a given 32 bits unsigned integer. Note: Note that in some languages, such as Java, there is no unsigned integer type. In this case, bo 阅读全文
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Given the root of a binary tree, return the preorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [1,2,3] Example 2: 阅读全文
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Given a string s consisting of words and spaces, return the length of the last word in the string. A word is a maximal substring consisting of non-spa 阅读全文
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Given an integer array nums of length n and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of t 阅读全文
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Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] 阅读全文
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You are given the head of a singly linked-list. The list can be represented as: L0 → L1 → … → Ln - 1 → Ln Reorder the list to be on the following form 阅读全文
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Given the head of a singly linked list, return true if it is a palindrome or false otherwise. Example 1: Input: head = [1,2,2,1] Output: true Example 阅读全文
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You are given the heads of two sorted linked lists list1 and list2. Merge the two lists in a one sorted list. The list should be made by splicing toge 阅读全文
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Given the heads of two singly linked-lists headA and headB, return the node at which the two lists intersect. If the two linked lists have no intersec 阅读全文
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Given the head of a linked list, return the list after sorting it in ascending order. Follow up: Can you sort the linked list in O(n logn) time and O( 阅读全文
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Given the head of a linked list, return the node where the cycle begins. If there is no cycle, return null. There is a cycle in a linked list if there 阅读全文