Counting the Prime Arrangements
Return the number of permutations of 1 to n so that prime numbers are at prime indices (1-indexed.) (Recall that an integer is prime if and only if it …
Category: math
Counting Substrings with Only One Distinct Letter with Different Algorithms
Given a string S, return the number of substrings that have only one distinct letter. Example 1: Input: S = “aaaba” Output: 8 Explanation: The substrings with one distinct …
How to Find the Largest Unique Number in Array using Javascript (Functional Programming)
Given an array of integers A, return the largest integer that only occurs once. If no integer occurs once, return -1. Example 1: Input: Output: 8 Explanation: The maximum …
Python Algorithm to Determine an Armstrong Number
The k-digit number N is an Armstrong number if and only if the k-th power of each digit sums to N. Given a positive integer N, return true if …
How to Multiply Two Matrices in C++?
Given two sparse matrices A and B, return the result of AB. You may assume that A’s column number is equal to B’s row number. Example: Input: A = …