CNoodle

摘要： Given an array of integers arr and an integer k. Find the least number of unique integers after removing exactly k elements. Example 1: Input: arr = [ 阅读全文

摘要： One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node's value. If it is a null node, 阅读全文

摘要： Given a binary array data, return the minimum number of swaps required to group all 1’s present in the array together in any place in the array. Examp 阅读全文

摘要： Given the root of a binary tree and two integers val and depth, add a row of nodes with value val at the given depth depth. Note that the root node is 阅读全文

摘要： Given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subsequence from s. Return the minimum number 阅读全文

摘要： Given an integer array nums and a positive integer k, return the most competitive subsequence of nums of size k. An array's subsequence is a resulting 阅读全文

摘要： Given a binary tree root, a node X in the tree is named good if in the path from root to X there are no nodes with a value greater than X. Return the 阅读全文

摘要： There is a special keyboard with all keys in a single row. Given a string keyboard of length 26 indicating the layout of the keyboard (indexed from 0 阅读全文

摘要： You would like to make dessert and are preparing to buy the ingredients. You have n ice cream base flavors and m types of toppings to choose from. You 阅读全文

摘要： You are given a 2D array of integers envelopes where envelopes[i] = [wi, hi] represents the width and the height of an envelope. One envelope can fit 阅读全文

摘要： You have a browser of one tab where you start on the homepage and you can visit another url, get back in the history number of steps or move forward i 阅读全文

摘要： You are given a string s and two integers x and y. You can perform two types of operations any number of times. Remove substring "ab" and gain x point 阅读全文

摘要： Given a string s, we make queries on substrings of s. For each query queries[i] = [left, right, k], we may rearrange the substring s[left], ..., s[rig 阅读全文

摘要： You have a set of integers s, which originally contains all the numbers from 1 to n. Unfortunately, due to some error, one of the numbers in s got dup 阅读全文

摘要： Given a 2D matrix matrix, handle multiple queries of the following type: Calculate the sum of the elements of matrix inside the rectangle defined by i 阅读全文

摘要： Implement FreqStack, a class which simulates the operation of a stack-like data structure. FreqStack has two functions: push(int x), which pushes an i 阅读全文

摘要： Given an integer array nums, handle multiple queries of the following type: Calculate the sum of the elements of nums between indices left and right i 阅读全文

摘要： Given two sequences pushed and popped with distinct values, return true if and only if this could have been the result of a sequence of push and pop o 阅读全文

摘要： An array is monotonic if it is either monotone increasing or monotone decreasing. An array A is monotone increasing if for all i <= j, A[i] <= A[j]. A 阅读全文

摘要： There are n buildings in a line. You are given an integer array heights of size n that represents the heights of the buildings in the line. The ocean 阅读全文