Suppose we have an array A with n elements, and also another number x. We know the lucky numbers are are positive numbers whose decimal representation only contains lucky digits 4 and 7. Form the given n positive integers. We have to count how many of those have not more ... Read More

Suppose we have two numbers n and x. First n natural numbers are written on a blackboard. In ith (i starts from 1) operation, we remove ith number from the blackboard. When there are less than i numbers, we stop removal task. We have to find x-th remaining number after ... Read More

Suppose we have three numbers a, b and c. There are three heaps of stones with a, b, and c number of stones respectively. Each time we can do these operations −Take one stone from the first heap and two stones from the second heap (when the heaps have necessary ... Read More

Suppose we have a number n. Let there is a hypothesis "There exists a positive integer n that for each positive integer m number (n·m + 1) is a prime number". We have to find such m as a counter example to disprove this statement.So, if the input is like ... Read More

Suppose we have a number x. We have to find two integers a and b, such that both of them will be in between 1 and x, a is divisible by b, a * b > x but a/b < x. If not possible, return -1. So, if the input ... Read More

Suppose we have three numbers x, y and z. On a review site there were x persons who would upvote, y persons who would downvote, and another group of z persons who would vote, but we do not know whether they would upvote or downvote. Each person can vote at ... Read More

Suppose we have an array D with n-1 elements and two values a and b. In an army, there are n ranks numbered from 1 to n. One needs D[i] years to rise from rank i to rank i+1. Amal has just reached new rank 'a' but he wants to ... Read More

Suppose we have an array of pairs P. Where P[i] is in the form (l, r), and have another number k. Consider we are going to read a book with n chapters. so that one page of the book belongs to exactly one chapter and each chapter contains at least ... Read More

Suppose we have a number n. Consider we are going to form an array A with n elements. A is sorted in ascending order and all elements are distinct. For every i from 2 to n (considering array index starts from 1) A[i] is not divisible by A[i-1].So, if the ... Read More

Suppose we have three numbers a, b and c. A singer has 'a' one-minute songs, 'b' tow-minutes song and 'c' three-minutes song. He wants to distribute all songs into two concerts, such that every song should be included to exactly one concert. He wants to make the absolute difference of ... Read More