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Math

A collection of 9 issues

Leetcode - Number of Good Pairs Solution

Given an array of integers nums. A pair (i,j) is called good if nums[i] == nums[j] and i < j. Return the number of good pairs. Example 1: Input: nums = [1,2,3,1,1,3] Output: 4 Explanation: There are 4 good pairs (0,3), (0,4)

Leetcode - Maximum 69 Number Solution

Given a positive integer num consisting only of digits 6 and 9. Return the maximum number you can get by changing at most one digit (6 becomes 9, and 9 becomes 6). Example 1: Input: num = 9669 Output: 9969 Explanation: Changing the first digit results in 6669. Changing the second

Leetcode - Subtract the Product and Sum of Digits of an Integer Solution

Given an integer number n, return the difference between the product of its digits and the sum of its digits. Example 1: Input: n = 234 Output: 15 Explanation: Product of digits = 2 * 3 * 4 = 24 Sum of digits = 2 + 3 + 4 = 9 Result = 24 - 9 = 15 Example 2: Input:

Leetcode - Self Dividing Numbers Solution

A self-dividing number is a number that is divisible by every digit it contains. For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0. Also, a self-dividing number is not allowed to contain the digit zero. Given a lower and upper number

Leetcode - Power of Three Solution

Given an integer n, return true if it is a power of three. Otherwise, return false. An integer n is a power of three, if there exists an integer x such that n == 3x. Example 1: Input: n = 27 Output: true Example 2: Input: n = 0 Output: false Example 3:

Leetcode - Happy Number Solution

Write an algorithm to determine if a number n is happy. A happy number is a number defined by the following process: * Starting with any positive integer, replace the number by the sum of the squares of its digits. * Repeat the process until the number equals 1 (where it will

Leetcode - Sqrt(x) Solution

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. Example 1: Input: x = 4 Output: 2 Example 2: Input: x = 8 Output: 2 Explanation:

Leetcode - Multiply Strings Solution

Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string. Note: You must not use any built-in BigInteger library or convert the inputs to integer directly. Example 1: Input: num1 = "2", num2 = "3" Output:

Hackerrank Polar Coordinates Solution

Polar coordinates are an alternative way of representing Cartesian coordinates or Complex Numbers. A complex number is completely determined by its real part and imaginary part . Here, is the imaginary unit. A polar coordinate () is completely determined by modulus and phase angle . If we convert complex number to its polar