Given a string s and a positive integer d, rearrange the characters of the string so that any two identical characters are at least d positions apart. If no such arrangement is possible, print "Cannot be rearranged". Examples: Input: s="abb", d = 2 Output: "bab" Explanation: The character 'a' and…

Given a number n, the task is to find the largest perfect cube that can be formed by deleting the fewest number of digits (possibly 0 digits). A number x is a perfect cube if it can be written as x = y3 for some integer y. You can delete any digits from the given number n, but you cannot rearrange…

Try it on GfG Practice Given a directed graph with n nodes and m edges. A source node and a destination node are also given, we need to find how many edges we need to reverse in order to make at least 1 path from the source node to the destination node. Note: In case there is no way then return -1.…

Given an array of integers arr[] of size m, representing the different type of tasks that need to be processed. We need to find the minimum processing cost required to assign these tasks to n processor cores. Each core can process one task at a time.Assigning a task to a core incurs a cost of 1 if…

Try it on GfG Practice Given a board of dimensions m × n that needs to be cut into m × n squares. The cost of making a cut along a horizontal or vertical edge is provided in two arrays: x[]: Cutting costs along the vertical edges (length-wise).y[]: Cutting costs along the horizontal edges…

Try it on GfG Practice Given the heights of n towers and a positive integer k, increase or decrease the height of all towers by k (only once). After modifications, the task is to find the minimum difference between the heights of the tallest and the shortest tower. Examples: Input: arr[] = [12, 6,…

Given an array of integers and an integer k, the task is to determine the maximum number of equal elements that can be achieved in the array by incrementing its elements. The total number of increments performed across all elements must not exceed k. Examples: Input : arr = [ 2, 4, 9 ], k = 3 Output…

Given a string s and an integer k, the task is to find lexicographically largest subsequence of S, say T, such that every character in T must occur at least k times. Examples: Input : s = "banana", k = 2. Output : "nn" Explanation: Possible subsequence where each character exists at least 2 times…

Try it on GfG Practice Given two integers s and d, find the smallest possible number that has exactly d digits and a sum of digits equal to s. Return the number as a string. If no such number exists, return "-1". Examples : Input: s = 9, d = 2 Output: 18 Explanation: 18 is the smallest number…

Given a very large integer n in the form of string, the task is to return the largest palindromic number obtainable by permuting the digits of n. If it is not possible to make a palindromic number, then return an empty string. Examples : Input : "313551" Output : "531135" Explanations : 531135 is…

We are given a matrix that contains different values in each cell. Our aim is to find the minimal set of positions in the matrix such that the entire matrix can be traversed starting from the positions in the set. We can traverse the matrix under the below conditions: We can move only to those…

A new variety of rice has been brought in supermarket and being available for the first time, the quantity of this rice is limited. Each customer demands the rice in two different packaging of size a and size b. The sizes a and b are decided by staff as per the demand. Given the size of the packets…

Given an array of integers arr[] of the even size n. Form the groups of two elements each from the given array arr[], such that the difference between the group with highest sum and the group with lowest sum is minimum. Your task is to find the minimum possible difference. Note: An element can be a…

Given a rectangular paper of dimensions a x b. The task is to cut the entire paper into the minimum number of square pieces. We can choose square pieces of any size, but they must be cut without overlapping or leaving any extra space. Examples: Input: a = 5, b = 8 5 squares cut from Paper of size 5…

Given a positive integer n, such that n > 2. Your task is to divide the numbers from 1 to n in two groups, such that the absolute difference between the sum of the elements of the these two groups is minimum possible. Examples: Input: n = 5 Output: [ [ 2, 5 ], [ 1, 3, 4 ] ] Explanation: The sum of…

Try it on GfG Practice We are given n-platform and two main running railway track for both direction. Trains which needs to stop at your station must occupy one platform for their stoppage and the trains which need not to stop at your station will run away through either of main track without…

Try it on GfG Practice In a candy store, there are N different types of candies available and the prices of all the N different types of candies are provided. There is also an attractive offer by the candy store. We can buy a single candy from the store and get at most K other candies (all are…

Given a number k, the task is to find the minimum number of Fibonacci terms (including repetitions) whose sum equals k. Note: You may use any Fibonacci number multiple times. Examples: Input: k = 7 Output: 2 Explanation: Possible ways to sum up to 7 using Fibonacci numbers: 5 + 2 = 7 (2 terms) 3 + 3…

Given an array arr[] of non-negative numbers. Each number tells you the maximum number of steps you can jump forward from that position. For example: If arr[i] = 3, you can jump to index i + 1, i + 2, or i + 3 from position i.If arr[i] = 0, you cannot jump forward from that position. Your task is to…

Given an amount, find the minimum number of notes of different denominations that sum up to the given amount. Starting from the highest denomination note, try to accommodate as many notes as possible for a given amount. We may assume that we have infinite supply of notes of values {2000, 500, 200,…

Try it on GfG Practice Given an array of n elements. Consider array as circular array i.e element after an is a1. The task is to find maximum sum of the difference between consecutive elements with rearrangement of array element allowed i.e after rearrangement of element find |a1 - a2| + |a2 - a3| +…

Try it on GfG Practice In a stock market, there is a product with its infinite stocks. The stock prices are given for N days, where arr[i] denotes the price of the stock on the ith day. There is a rule that a customer can buy at most i stock on the ith day. If the customer has k amount of money…

Try it on GfG Practice Given two arrays, greed[] and cookie[] such that greed[i] denotes the minimum cookie size wanted by ith child and cookie[i] denotes the size of ith cookie, the task is to find the maximum number of children that can be satisfied by assigning them cookies, with each child…

Try it on GfG Practice Given an array of n integers. We need to reduce size of array to one. We are allowed to select a pair of integers and remove the larger one of these two. This decreases the array size by 1. Cost of this operation is equal to value of smallest one. Find out minimum sum of costs…

Try it on GfG Practice Given an array of non-negative integers, the task is to find the minimum number of elements such that their sum should be greater than the sum of the rest of the elements of the array. Example: Input: arr[] = [ 3 , 1 , 7, 1 ] Output: 1 Explanation: Smallest subset is {7}. Sum…

Given n, print the maximum number of composite numbers that sum up to n. First few composite numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, ……… Examples: Input: 90 Output: 22 Explanation: If we add 21 4's, then we get 84 and then add 6 to it, we get 90. Input: 10 Output: 2 Explanation: 4 + 6 =…

Try it on GfG Practice You are given a lock which is made up of n-different circular rings and each ring has 0-9 digit printed serially on it. Initially all n-rings together show a n-digit integer but there is particular code only which can open the lock. You can rotate each ring any number of time…

A greedy algorithm solves problems by making the best choice at each step. Instead of looking at all possible solutions, it focuses on the option that seems best right now. Example of Greedy Algorithm - Fractional Knapsack Problem structure: Most of the problems where greedy algorithms work follow…

Greedy is an algorithmic paradigm that builds up a solution piece by piece, always choosing the next piece that offers the most obvious and immediate benefit. Greedy algorithms are used for optimization problems. An optimization problem can be solved using Greedy if the problem has the following…

Try it on GfG Practice Given two arrays a[] and b[] of size m and n respectively, the task is to determine whether b[] is a subset of a[]. Both arrays are not sorted, and elements are distinct. Examples: Input: a[] = [11, 1, 13, 21, 3, 7], b[] = [11, 3, 7, 1] Output: true Input: a[]= [1, 2, 3, 4, 5,…

Given an array of pairs arr[], a pair (a, b) is said to be symmetric with (c, d) if b = c and a = d. In other words, reversing the elements of one pair should result in the other pair. The first element of each pair is guaranteed to be distinct. Examples: Input: arr[] = [[10, 20], [30, 40], [20,…

Separate Chaining is a collision handling technique. Separate chaining is one of the most popular and commonly used techniques in order to handle collisions. In this article, we will discuss about what is Separate Chain collision handling technique, its advantages, disadvantages, etc. There are…

Open Addressing is a method for handling collisions. In Open Addressing, all elements are stored in the hash table itself. So at any point, the size of the table must be greater than or equal to the total number of keys (Note that we can increase table size by copying old data if needed). This…

Try it on GfG Practice Given an array arr[] of size n, the task is to print all subarrays in the array which has sum 0. Examples: Input: arr = [6, 3, -1, -3, 4, -2, 2, 4, 6, -12, -7] Output: Subarray found from Index 2 to 4 Subarray found from Index 2 to 6 Subarray found from Index 5 to 6 Subarray…

Given an array, arr[0..n-1] of distinct elements and a range [low, high], find all numbers that are in a range, but not the array. The missing elements should be printed in sorted order. Examples: Input: arr[] = {10, 12, 11, 15}, low = 10, high = 15 Output: 13, 14 Input: arr[] = {1, 14, 11, 51, 15},…

Try it on GfG Practice Given an array of integers, the task is to find the length of the longest subsequence such that elements in the subsequence are consecutive integers, the consecutive numbers can be in any order. Examples: Input: arr[] = [2, 6, 1, 9, 4, 5, 3] Output: 6 Explanation: The…

In this article, we will understand the internal workings of the HashMap in Java, also how the get() and put() method functions, how hashing is done, how key-value pairs are stored, and how the values are retrieved by keys. Basic Structure of a HashMap HashMap contains an array of Node objects. Each…

Try it on GfG Practice Given an array of integers and a number k, write a function that returns true if the given array can be divided into pairs such that the sum of every pair is divisible by k. Examples: Input: arr[] = [9, 7, 5, 3], k = 6 Output: True We can divide the array into (9, 3) and (7,…

All data structure has their own special characteristics, for example, a BST is used when quick searching of an element (in log(n)) is required. A heap or a priority queue is used when the minimum or maximum element needs to be fetched in constant time. Similarly, a hash table is used to fetch, add…

Try it on GfG Practice Given an array of integers arr[] and a number k, the task is to count the number of subarrays having XOR of their elements as k. Examples: Input: arr[] = [4, 2, 2, 6, 4], k = 6 Output: 4 Explanation: The subarrays having XOR of their elements as 6 are [4, 2], [4, 2, 2, 6, 4],…