Problem You have observations of n + m 6-sided dice rolls with each face numbered from 1 to 6. n of the observations went missing, and you only have the observations of m rolls. Fortunately, you have also calculated the average value of the n + m rolls. You are given an integer array rolls of length m where rolls[i] is the value of the ith observation. You are also given the two integers mean and n. ...
Problem Assume you have access to a function toss_biased() which returns 0 or 1 with a probability that’s not 50-50 (but also not 0-100 or 100-0). You do not know the bias of the coin. Write a function to simulate an unbiased coin toss. Solution Method 1 - Using Probability To simulate an unbiased coin toss using a biased coin, we can use a clever trick that leverages pairs of results. Specifically, we can use the pair (0, 1) and (1, 0) to generate unbiased results. The idea is that these pairs are equally likely to occur, regardless of the bias of the original coin. ...
Problem There are numBottles water bottles that are initially full of water. You can exchange numExchange empty water bottles from the market with one full water bottle. The operation of drinking a full water bottle turns it into an empty bottle. Given the two integers numBottles and numExchange, return the maximum number of water bottles you can drink. Examples Example 1: Input: numBottles = 9, numExchange = 3 Output: 13 Explanation: You can exchange 3 empty bottles to get 1 full water bottle. Number of water bottles you can drink: 9 + 3 + 1 = 13. ...
Problem Given an integer array nums and an integer k, return true if nums has a continuous subarray of size at least two whose elements sum up to a multiple of k, or false otherwise. An integer x is a multiple of k if there exists an integer n such that x = n * k. 0 is always a multiple of k. Examples Example 1: ...
Problem Implement pow(x, n), which calculates x raised to the power n (i.e., x^n). Examples Example 1: Input: x = 2.00000, n = 10 Output: 1024.00000 Example 2: Input: x = 2.10000, n = 3 Output: 9.26100 ...
Problem Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array. Examples Example 1: Input: nums = [3,0,1] Output: 2 Explanation: n = 3 since there are 3 numbers, so all numbers are in the range [0,3]. 2 is the missing number in the range since it does not appear in nums. ...
Problem Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0. Assume the environment does not allow you to store 64-bit integers (signed or unsigned). Examples Example1: x = 123, return 321 Example2: x = -123, return -321 ...
Problem Determine whether an integer is a palindrome. Follow up Do this without extra space. Definition Palindrome Definition Examples Example 1: Input: x = 121 Output: true Explanation: 121 reads as 121 from left to right and from right to left. Example 2: Input: x = -121 Output: false Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome. ...
Problem Given a string expression representing an expression of fraction addition and subtraction, return the calculation result in string format. The final result should be an irreducible fraction. If your final result is an integer, change it to the format of a fraction that has a denominator 1. So in this case, 2 should be converted to 2/1. Examples Example 1: Input: expression = "-1/2+1/2" Output: "0/1" ...
Problem Given the coordinates of four points in 2D space p1, p2, p3 and p4, return true if the four points construct a square. The coordinate of a point pi is represented as [xi, yi]. The input is not given in any order. A valid square has four equal sides with positive length and four equal angles (90-degree angles). Examples Example 1: Input: p1 = [0,0], p2 = [1,1], p3 = [1,0], p4 = [0,1] Output: true ...