My software development journey
Given a string, we need to check if a string is a double string possibly by deleting a character. A double string is a repetition of two strings affixed together. For example the following strings are double strings “aa”, “meme”, “abbabb” Where as the follwing are not double strings “ab”, “abc”, “acbab” However “acbab” can…
This problem is from the recently concluded Facebook Hackercup 2016 Qualification round. You can take a look at the problem statement in this link. I am giving the abridged problem statement here. Given a set of coordinates in a 2D-plane, We have to find out the total number of pairs of lines with equal length…
Given an array A of distinct numbers, how to count the number of pairs (i,j) such that A[i] < A[j] For example, let us consider A = [2, 1, 3] the pairs are (1,2), (1,3), (2,3). So there are 3 pairs. Similarly for A = [10, 6, 9, 2], there are 6 pairs This problem…
Given some amount N, and a set of denominations, how do you find the number of ways to make change for N? Let us assume that there is infinite supply of coins for each denomination. For example, if we have to make change for 4, and the given denominations are {1, 2, 3}, the possibilities…
Given an array of numbers, how to find the maximum length of increasing (non-decreasing) continuous sub-sequence? For example consider the array [7, 9, 1, 3, 5, 8, 2], the maximum length is 4. Similarly for [23, 10, 18, 18, 6], it is 3. This is a straight forward implementation problem (appeared on Codeforces). Following is…
Given an array of numbers and a sum, how to check if there is any sub-array with the given sum. For example consider an array A = [7, 2, 9, 1, 5], and the sum is 12, then we can find a sub-array [2, 9, 1] which sums up to 12. So the answer is…
Given a number K, Find the shortest and smallest string which has K positions in it, such that the character at that position is alphabetically greater than the character immediately after it. Only the lower case alphabets [a-z] are allowed. For example consider K = 1 “ba” is the shortest and smallest string possible. There…
Given an array, how do we find the minimum difference between any two elements in that array? For example consider the array [56, 18, 89, 24, 10], the minimum difference is 6 (between 18, and 24). A straight forward method to find the minimum difference between any two pairs is to iterate through each possible…
Given an array of numbers A[N], how do we arrange them in the following order. A[0] <= A[1] >= A[2] <= A[3]…A[N-1] For example consider the array A =[6, 9, 36, 24, 42] The answer can be [6, 36, 9, 42, 24]. There can be multiple answers also like [6, 42, 9, 36, 24]. We…
Given an array of numbers, how do we search for a given number? For example, given an array [6, 50, 24, 36, 42], the number 36 is present at the index 3 starting with 0. The number 17 is not present any where. The simplest algorithm to solve this problem is to check each element…