Difficulty/Easy

Problem Given an integer rowIndex, return the rowIndexth (0-indexed) row of the Pascal’s triangle. In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown: ...

Reverse Words in a String 3 Problem Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Examples Example 1: Input: s = "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc" Example 2: Input: s = "God Ding" Output: "doG gniD" ...

Problem Implement int sqrt(int x). OR Compute and return the square root of x. OR If x is not a perfect square, return floor(sqrt(x)) OR floor(√n) OR Given a non-negative integer x, compute and return the square root of x. Since the return type is an integer, the decimal digits are truncated, and only the integer part of the result is returned. ...

Problem A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Write a function to determine if a number is strobogrammatic. The number is represented as a string. Examples Example 1: Input: "69" Output: true Example 2: Input: "88" Output: true ...

Problem A sequence of numbers is called an arithmetic progression if the difference between any two consecutive elements is the same. Given an array of numbers arr, return true if the array can be rearranged to form an arithmetic progression. Otherwise, return false. Examples Example 1: Input: arr = [3,5,1] Output: true Explanation: We can reorder the elements as [1,3,5] or [5,3,1] with differences 2 and -2 respectively, between each consecutive elements. ...

Problem You are given a string s consisting of lowercase English letters. A duplicate removal consists of choosing two adjacent and equal letters and removing them. We repeatedly make duplicate removals on s until we no longer can. Return the final string after all such duplicate removals have been made. It can be proven that the answer is unique. Examples Example 1: Input: s = "abbaca" Output: "ca" Explanation: For example, in "abbaca" we could remove "bb" since the letters are adjacent and equal, and this is the only possible move. The result of this move is that the string is "aaca", of which only "aa" is possible, so the final string is "ca". ...

Problem Given an integer array nums and an integer k, return the number of pairs (i, j) where i < j such that |nums[i] - nums[j]| == k. The value of |x| is defined as: x if x >= 0. -x if x < 0. Examples Example 1: Input: nums = [1,2,2,1], k = 1 Output: 4 Explanation: The pairs with an absolute difference of 1 are: - [1̲,2̲,2,1] - [1̲,2,2̲,1] - [1,2̲,2,1̲] - [1,2,2̲,1̲] ...

Problem Given an integer array arr and a filtering function fn, return a filtered array filteredArr. The fn function takes one or two arguments: arr[i] - number from the arr i - index of arr[i] filteredArr should only contain the elements from the arr for which the expression fn(arr[i], i) evaluates to a truthy value. A truthy value is a value where Boolean(value) returns true. ...

Problem Given a positive integer n, find and return the longest distance between any two adjacent 1’s in the binary representation of n. If there are no two adjacent 1’s, return 0. Two 1’s are adjacent if there are only 0’s separating them (possibly no 0’s). The distance between two 1’s is the absolute difference between their bit positions. For example, the two 1’s in "1001" have a distance of 3. ...

Problem Given two non-negative integers low and high. Return the count of odd numbers between low and high (inclusive). Examples Example 1: Input: low = 3, high = 7 Output: 3 Explanation: The odd numbers between 3 and 7 are [3,5,7]. Example 2: Input: low = 8, high = 10 Output: 1 Explanation: The odd numbers between 8 and 10 are [9]. ...