Find all duplicate elements in a limited range array
Find the duplicate numbers in an integer array of size n that contains elements between 1 and n, at least one of which repeats.
Tag: Hashing
Count quadruplets with a zero sum
Given four integer arrays, count the number of quadruplets with a zero sum, including exactly one element from each array.
Find length of the longest palindrome possible from a string
Given a string, find the length of the longest palindrome possible from its characters.
Count paths with the given sum in a binary tree
Given a binary tree and an integer k, count the total number of paths in the tree whose sum of all nodes is equal to k.
Check if a string can be constructed from another string
Given two strings, check if the second string can be constructed from characters of the first string, where each character of the first string can be used only once in the second string.
Find the smallest missing positive number from an unsorted array
Given an unsorted integer array, find the smallest missing positive integer in it.
Remove loop from a linked list
Given a linked list containing a loop, remove the loop from it.
Find itinerary from the given list of departure and arrival airports
Given a list of departure and arrival airports, find the itinerary in order. It may be assumed that departure is scheduled from every airport except the final destination, and each airport is visited only once.
Determine whether an array can be divided into pairs with a sum divisible by `k`
Given an integer array, determine if it can be divided into pairs such that the sum of elements in each pair is divisible by a given integer k.
Find the intersection point of two linked lists
Given two linked lists, where the tail of the second list points to a node in the first list, find the node where both lists intersect.
Find all substrings containing exactly `k` distinct characters
Given a string and a positive integer k, find all distinct substrings of any length containing exactly k distinct characters.
Longest Consecutive Subsequence
Given an integer array, find the length of the longest subsequence formed by the consecutive integers. The subsequence should contain all distinct values, and the character set should be consecutive, irrespective of its order.