# Tag Archives: Puzzle

## Container with maximum water

Question: Let us suppose we have a two dimensional plane where the the length of lines determine the height of a container. We need to determine the maximum capacity of water this kind of an arrangement can hold. The heights are represented by an array. Input: [1, 8, 6, 2, 5, 4, 8, 3, 7] Output: 49 Let… Read More »

## Find the first N prime numbers. (Method 4) [Sieve of Eratosthenes]

Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 We have several ways of finding prime numbers. Some of the methods are discussed in the these posts. Method 1 Method 2 Method 3 In this post we… Read More »

## Find the sum of even Fibonacci numbers.

Question: Find the sum of even fibonacci numbers upto a limit N. Input:100 Output: 44 Fibonacci numbers are a miracle of Math and are defined as:- f(0) = 0 f(1) = 1 f(n) = f(n-1) + f(n-2); for n>=2 Thus the Fibonacci series can be given as 0, 1, 1, 2, 3, 5, 8, 13, 21… Let us… Read More »

## [Hackerrank] – Multiples of 3 and 5

Question: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below ‘N’ Input: N = 100 Output: 2318 The most naive approach to solve this problem… Read More »

## Convert a number into a string of words

Question: Given an integer N, convert it into a string of words. Input: N = 345 Output: three hundred forty five This is one of the most common problems that we come across in out daily lives. We need to input a number from the user and print it in words. First, we perform a number of checks… Read More »

## Find the first N prime numbers. (Method 3)

Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 We discussed the basic approaches to find the first N prime numbers in these posts Find the first N prime numbers (Method 1) Find the first N prime… Read More »

## Find the first N prime numbers. (Method 2)

Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 We discussed the most basic approach to find the first N prime numbers in this post. Find the first N prime numbers. (Method 1) Please go through the… Read More »

## Find the first N prime numbers. (Method 1)

Question: Given an integer N, find the prime numbers in that range from 1 to N. Input: N = 25 Output: 2, 3, 5, 7, 11, 13, 17, 19, 23 Today let us discuss about a very common but very interesting problem “To find prime numbers in first N Natural numbers “. I will be taking here a… Read More »

## Determine if 2 rectangles overlap

Question: You are given two axis-aligned rectangles. You have to determine if these rectangles overlap each other or not. Rectangle 1 : P1 (x, y), P2 (x,y) Rectangle 2 : P3 (x,y), P4 (x,y) In this problem statement, we are given co-ordinates for 2 rectangles and we have to determine if they overlap or not. In a way… Read More »

## Easiest way to change case of alphabets

Here we will discuss the easiest and most simple way to change case of alphabets. Hint : We will be using bit hacks. Often during our programming needs we need to change the case of alphabets. This can be a problem requirement or simply our need to solve the question. There are several ways to do it, but… Read More »