A valid mathematical expression can also have duplicate parenthesis as shown below:
((a+b)) (((a+(b)))+(c+d))
Write code to find if an expression has duplicate parenthesis. You may assume that expression does not have any white spaces. Continue reading »
Print Next Greater Element for every element in the array. The Next greater Element of element x is first greater element on its right side.
Elements for which no greater element exist, next greater element is -1.
Example:
- For any array, rightmost element always has next greater element as -1.
- All elements of an array sorted in decreasing order have next greater element as -1.
- For input array {5, 9, 1, 15}, the next greater elements of each element are as follows.
{9, 15, 15, -1}
- For input array {20, 17, 15, 10}, the next greater elements are {-1, -1, -1, -1}
Binary tree is a specialization of Graph data structure. Node in a Graph is called a Vertex and the connection between two vertices is called an Edge.
If we use this terminology, A Binary tree edge is only from a parent to its (at the most two) children. In Graph, any vertex (Node) can connect to any vertex and there is no limit on the number of vertices that a vertex can connect to. The connection can be uni-directional (as in Binary trees) or bi-directional. When connections are uni-directional the edge is called directed edge and graph is called directed graph. When connections are bi-directional, edge is called un-directed edge and graph is called undirected graph. Because of these connections, there is no hierarchy among the vertices of a Graph. Continue reading »
We discussed Insertion sort in detail earlier. This post shows the recursive implementation of Insertion Sort. Continue reading »
Given a sorted array of numbers and a number x, count the number of occurrences of x in the array.
Input:
int arr[] = {1, 3, 3, 4, 4 ,5, 5, 5, 7, 8, 8}; int x = 5;
Output:
3
It is used when there are few unique elements in an array. Counting sort takes O(n+k) time in the worst case, where n is number of elements and all the elements are in the range 1 to k (both inclusive). Continue reading »
This question is from exercise in my book Dynamic Programming for Coding Interviews (Question: 1.2, Page-5)
Question: Given an array, arr of integers, write a recursive function that add sum of all the previous numbers to each index of the array. For example, if the input array is
{1, 2, 3, 4, 5, 6}
then your function should update the array to
{1, 3, 6, 10, 15, 21}
Given two sorted arrays of size m and n respectively. Also given an empty third array of size (m+n). write code to merge the two arrays and store the result in the third array.
INPUT ARRAYS:
a = {1, 4, 5, 9}
b = {0, 2, 3, 7, 15, 29}
OUTPUT:
c = {0, 1, 2, 3, 4, 5, 7, 9, 15, 29}
The structure of Node of a Binary Tree and Doubly linked list are same.
struct Node
{
int data;
Node* left;
Node* right;
}
Structure of Node of a Binary Tree |
struct Node
{
int data;
Node* previous;
Node* next;
}
Structure of Node of a Doubly linked list |
If we treat left pointer as previous and right pointer as next, we can use the Node of a Binary Tree to represent node of a Doubly linked list or vice-versa.
Given a binary tree, modify the pointers in each node of the tree so that they represent a Doubly linked. Order of the nodes in DLL should be same as that in the in-order traversal.
If the Input Binary tree is as below
then the function should modify pointers in the nodes, as shown below and return the head pointer.
Given an array of numbers find the maximum XOR value of two numbers in the array.
Input Array = {12, 15, 5, 1, 7, 9, 8, 6, 10, 13};
Output = 15 (XOR of 5 and 10)
5 = 0101
10 = 1010
---------
XOR = 1111