Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]"
我会尽力将LeetCode上所有的题目都用动画的形式演示出来,期待与你见证这一天! GitHub Repo:LeetCode Animation Follow: MisterBooo · GitHub Problems ID Problem Article Animation 001 两数之和 每天一算:Two Sum 019 删除链表的倒数第N个节点 每天一算:Remove Nth Node From End of List 020 有效的括号 每天一算:Valid Parentheses 0
Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct
Given an integer array nums, return the number of range sums that lie in [lower, upper] inclusive.Range sum S(i, j) is defined as the sum of the elements in nums between indices i and j (i ≤ j), inclusive. Note:A naive algorithm of O(n2) is trivial.
Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of the subtree have the same value. For example:Given binary tree, 5 / \ 1 5 / \ \ 5 5 5 return 4. 这道题让我们求相同值子树的个数,就是所有节点值都相同的子树的个数,之前有道求最大BST子树的题Largest
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. For example, Given [3,2,1,5,6,4] and k = 2, return 5. Note: You may assume k is always valid, 1 ≤ k ≤ array'
There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). 这道题让我们求两个有序数组的中位数,而且限制了时间复杂度为O(log (m+n)),看到这个时间复杂度,自然而然的想到了应该使用二分查找法来求解.但是这道题
