# Data Structure Problems

 Matching BracketsYou will be given a sequence of opening and closing brackets of different types ((, ), [, ], {, and ... Very Easy 860/955/2k Neat BracketsGiven a sequence of opening and closing parentheses ("(" and ")") you will have to determine if it i... Very Easy 1k/1k/4k Exists or Not ExistsYou will be given some numbers. Then there will contain some queries. In every query there will be g... XOR TreeYou are given a tree with N vertices. A tree is a connected undirected graph without cycles. The tre... Moderate 16/18/50 Counting FriendsJohnny uses a social network called Supernova. Unlike the other social networks, Supernova does not ... Moderate 75/113/288 Count the ChaosImagine, you have an array of integers of size N. At each index of this array is a unique integer fr... Laser LightA 2D grid consists of a lot of special lights bulbs, which turns on upon the incidence of a laser li... Set UnionGiven two sets of integers, print the set containing the union of the two input sets. For example, g... Very Easy 1k/1k/3k Holy TreeWhat is a tree? A tree is a bidirectional connected graph with no cycle. In a tree, we can create ... Moderate 24/41/140 Cut the RopeFahim is a rope seller. He has a special tool for cutting ropes. But recently this tool is behaving ... Village Fair 2There are N houses in a village far away from here. They are numbered from 1 to N. For this problem ... Moderate 21/40/238 DistinctnessA substring of string S is another string S' which occurs in string S. For example: S = aaba and one... Mario and Princess PeachThe world of Mario can be imagined as 2D grid of \$N\$ rows and \$M\$ columns--containing a total of \$N ... Final Days of GoldfingerWe see agent Bond once again being called in time of a great need. The vile criminal Auric Goldfinge... Smart Query HandlerBit operators perform bit-wise operations between two binary numbers. Wikipedia says, binary operati... Moderate 54/74/215 Distinct DishtingYou are given an array of N integers. Then there will be Q commands of the following type: Change ... Primary Key"Clarity-Lon" is the new awesome e-commerce based startup that went to the top of the chart within f... Earthquake!Most houses are not as safe as they could be. Earthquake engineering is an interdisciplinary branch ... Moderate 13/17/23 Expandable ListViewMinas is working on his new language. He want to add a feature call expandable listview. Here he exp... Moderate 10/11/20 Rio and InversionOne day Rio was returning home from his university and unfortunately lost his phone on the way. He a... Moderate 43/50/218 New Year CoupleThe new year 2017 is here. To celebrate the 31st night, Mr Rio has thrown a big party at his house. ... Moderate 22/32/170 Subarray SumYou are given an array having N integers. You have to select at most K positions in the array and re... Moderate 134/190/840 Sofdor Ali and Bracket SequenceSofdor Ali has invented a new game. He asked his assistant Jong Bahadur ( who happens to be a monkey... Smallest SubarrayYou are given an array A of N integers A1, A2, A3, ..., AN . If we select two indices (1 ≤ i ≤ j ≤ N... Moderate 26/35/100 Special PairMr. X is an “array pagla” person. He loves doing different types of things with arrays. Today Mr. X ...