Majority Element – Part 1
Objective: Given an array of integer write an algorithm to find the majority element in it (if exist). Majority Element: If an element appears more than n/2 times in array where n is the size...
Category: Arrays
Find the local minima in a given array
Objective: Given an array of integer write an algorithm to find the local minima. Local Minima: An element is considered as local minima if it is less than both of its neighbors (if neighbors exist)....
Check if array is sorted using recursion
Objective: Given an array of integer write a recursive solution to check if array is sorted. Example: int [] a = {1,2,3,4}; Output: true int [] a = {1,2,3,4,2}; Output: false Approach: This problem can...
Find the Index from which 0 starts
Objective: Given an array of integer which 1’s followed by 0’s. Find the starting index of 0. Example: int [] a = {1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0}; First Index from where 0 starts: 10 int [] a = {1,1,1}; ...
Find the increasing OR decreasing point in an array
Objective: Given an array of integer which is first increasing then decreasing. Find the element in array from which point it starts decreasing. OR Given an array of integer which is first increasing then decreasing....
Find the only element in array which appears only once
Objective: Given an array of integers, all the elements are appear twice but one element which appears only once. Write an algorithm to find that element. Example: int [] a = { 1,5,6,2,1,6,4,3,2,5,3}; output:...
Stock Single Sell Problem – O(n) Solution
Objective: Given an array represents cost of a stock on each day. You are allowed to buy and sell the stock only once. Write an algorithm to maximize the profit in single buy and sell....
Maximum Subarray OR Largest Sum Contiguous Subarray Problem – Divide and Conquer
Objective: The maximum subarray problem is the task of finding the contiguous subarray within a one-dimensional array of numbers which has the largest sum. Example: int [] A = {−2, 1, −3, 4, −1, 2, 1, −5, 4}; Output:...
Maximum difference between two elements where larger element appears after the smaller element
Objective: Given an array A[], write an algorithm to find Maximum difference between two elements where larger element appears after the smaller element or in other words find A[i] and A[j] such that A[j]-A[i]...
Find the two repeating elements in a given array | 6 Approaches
Objective: Given an array of n+2 elements. All elements of the array are in range 1 to n and all elements occur once except two numbers which occur twice. Write an algorithm to find...
Find two elements whose sum is closest to zero
Objective: Given an array of positive and negative integers, write a algorithm to find the two elements such their sum is closest to zero. Example: int a [] = {1, 4, -5, 3, -2,...
Find the element which appears maximum number of times in the array.
Objective: Given an array of integers, write a algorithm to find the element which appears maximum number of times in the array. Example: int [] arrA = {4, 1, 5, 2, 1, 5, 9,...
Find duplicates in an given array in O(n) time and O(1) extra space.
Objective: Given an array of integers, find out duplicates in it. Example: int [] a = {4, 6, 2, 1, 2, 5}; Output: Array has duplicates : 2 int a [] = {1, 6,...
Find the last non repeating character in a given string.
Objective: Given a string, write an algorithm to find the last non repeating character in it. Example: String input = “algorithms tutorials” Output: ‘u’ String input = “aabbccdd” Output: No repeating character found. Approach:...
Find the last repeating character in a given string.
Objective: Given a string, write an algorithm to find the last repeating character in it. Example: String input = “horizon tutorials” Output: ‘i’ String input = “algorithms” Output: No repeating character found. Approach: Naive...