My software development journey
Given two arrays of numbers, how to check if the first sequence is a sub sequence of second sequence.For example [3, 7, 11] is a sub-sequence of [9, 3, 1, 7, 5, 11]where as [4, 8, 9] is not a sub-sequence of [6, 4, 9, 2, 8]The algorithm here is simple. Let us assume two…
Given an array of numbers ( minimum length 3), find an index such that all the elements to the left of it are less than or equal, and all the elements to the right of it are greater than it. For example in the array [1, 2, 3], the pivot element is 2, as all…
Given a permutation of numbers from 1 to N, We can represent it in two ways. For example, let us consider a permutation from 1 to 5 P = [2 4 1 5 3] This representation directly indicates the position of each number. i.e 2 is first, 4 is second and so on. Alternatively, this…
Given an array of numbers A, which might contain duplicate elements, How do we find if there are two elements A[i], A[j] such that i, j are distinct and the difference between them is at most k? Look at the following examples.1. A = [9, 5, 6, 9, 3, 0, 1], K =3The answer is…
Given an array of elements, how do we find the XOR of each sub-array and XOR of those results? For example let us consider the array [1, 2, 3], all possible sub-arrays are XOR[1] = 1XOR[1, 2] = 1 ^ 2 = 3XOR[1, 2, 3] = 1 ^ 2 ^ 3 = 0XOR[2] = 2XOR[2,…
Given a string, We have to find out by removing which character, it becomes a palindrome.For example consider the string “racercar”, the character ‘r’ at index 4 should be removed to become a palindrome.The approach here is simple. Start from both ends of the string and compare both characters. If they are equal, we increment…
Radix sort is an integer sorting algorithm. As it’s name indicates, it sorts a list of numbers based on the digits of the numbers. It’s a linear time sorting algorithm which is different from the comparison based sorting algorithms like quick sort or heap sort. Counting sort is also a linear time sorting algorithm which…
Given an array of integers (positive and negative), how do we find a longest sub-array with zero sum? For example, consider the example [5, 0, -1, 3, -2, 4], the longest sub array with zero sum contains 4 elements. The straight forward approach is to check the sum of all possible arrays and find out…
Given an array of numbers A[1:N], we have to generate a product array P[1:N] such that P[i] contains the product A[1]*…A[i-1]*A[i+1]…A[N] That means each entry in the product array should contain product off all the elements except the one at that particular index. For example let us consider the array [4, 2, 10, 5], the…
Here is the link to the original problem. Let us try to simplify the problem statement a little bit. There is a dinner house of infinite number of guests but finite number of pancakes. Each of them hold a plate which is either empty or has some pancakes in them. Every minute, one of the…