My software development journey
Anagram of a word is nothing but rearrangement of it’s letters to form another word.For example ‘listen’ is an anagram of ‘silent’ and ‘enlist’.We have to write a function to check if two given strings are anagrams are not. We can solve this problem in two different ways. The first way is to sort the…
Given an array, and a value K as input, we have to find a pair of elements such that their sum is K. There are multiple ways of solving this problem. We will discuss some of them in this post. Let us implement the function which prints the two values such that array[i] + array[j]…
Let us consider an array of size N contains numbers in the range [1,N]. We have to find if it has duplicates in linear time – O(n) and by using only constant extra space – O(1). Let us also have a restriction that we should traverse the array only once. Take a look at the following…
Given two strings, How do we delete all the characters in the first string which are present in the second string? Find the character set of the string. Create a Boolean array of size equal to the character set size. If the character set is ASCII, the size is 256. This array will be indexed…
How do you implement a stack using Queue? This is the exact reverse of the problem discussed in my earlier post. We have to use only Queue operations like enqueue(), dequeue() and size() operations to implement push() and pop() operations of the stack. This can be done using two queues. One queue acts as the…
How to implement a Queue data structure using Stack? We have to use only the operations that are supported by Stack ADT*. The methods supported by stack are push(), pop(), and isEmpty(). We have to use only these three operations to implement a Queue. The Queue data structure should primarily support enqueue() and dequeue() operations.…
Given an array of numbers, we have to find the longest sub sequence of that array which is strictly increasing.For example in the following array [8 1 4 2 7 9 5] {8,9}{1,4,7,9}{1,2,7,9}{1,2,5}{1,2,7}{1,2,9} are some of the increasing sub-sequences. The second and third are the longest increasing sub sequences with length 4. Our job is…
An array of size (n-1) contains all the numbers in the range [1..n] except one number which is missing. Write a program to find the missing number in O(n) time and O(1) space. For example let N= 5 and the input array is [1,3,4,5], the output should be 2. Given O(n) space we can always…
In this post we will discuss a simple problem on Arrays. Given an array of numbers, how do we reverse it efficiently? Here is the simple and effective approach. We start with one index pointing to the start, and another index pointing to the end of the array. We swap the two elements at these…