Combinatorial - Hard Articles

Counting numbers with given digits and digit sum

Given a number N, count the numbers X of length exactly N such that the number X and the sum of digits of the number… Read More

Binary Exponentiation

number-theory

Picked

Combinatorial

Competitive Programming

DSA

Count Weird Triplets

Given an array A[] of integers. Your task is to output the count of triplets such that in each triplet, there can be at most… Read More

combinatorics

Geeks Premier League 2023

math

python-dict

Scala-Arrays

Combinatorial

DSA

Count of permutations of size 2N with at least N increasing elements

Given N, the task is to determine the count of all permutations of size 2N having at least N-increasing elements. An element pi of a… Read More

Picked

Combinatorial

DSA

Count of ways to form N digit number div by 3 with no adjacent duplicates

Given integer N, the task is to count the number of ways( modulo 109 + 7) to create an N digit number from digits 1… Read More

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Technical Scripter

Count ways to create string of size N with given restrictions

Given a number N, the task is to count the number of ways to create a string of size N (only with capital alphabets) such… Read More

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Technical Scripter

Count ways to generate N digit number such that its every digit divisible by previous digit

Given a number N, the task is to count the number of ways to create an N digit number from digits 1 to 9 such… Read More

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Technical Scripter

Count ways of selecting X red balls and Y blue balls

Given integers A, B, C, and D, There are two boxes First Box has A red balls and B blue balls and the second box… Read More

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Technical Scripter

Count ways choosing K balls from any given A boxes

Given integers A and K, there are A boxes the first box contains K balls, the Second box contains K + 1 balls, the Third… Read More

Modular Arithmetic

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Technical Scripter

Count number of ways in which following people can be arranged

Given integers X and Y representing X girls and Y boys, the task is to count the number of ways arranging X girls and Y… Read More

Modular Arithmetic

Technical Scripter 2022

Combinatorial

DSA

Technical Scripter

Count binary Strings that does not contain given String as Subsequence

Given a number N and string S, count the number of ways to create a binary string (containing only ‘0’ and ‘1’) of size N… Read More

strings

Technical Scripter 2022

Combinatorial

DSA

Dynamic Programming

Strings

Technical Scripter

Count ways to traverse all N cities when each city is traversed K times

For N given cities, find how many ways a driver can traverse through them so that each town is visited exactly K times. From each… Read More

Combinatorial

Competitive Programming

DSA

Dynamic Programming

Mathematical

Count ways to choose Triplets of Pairs such that either first or second values are distinct

Given an array of pairs arr[] of size N (N ? 3) where each element of pair is at most N and each pair is… Read More

combinatorics

cpp-pair

Arrays

Combinatorial

DSA

Mathematical

Find all unique subsets of a given set using C++ STL

Given an array arr[] of integers of size N that might contain duplicates, the task is to find all possible unique subsets, using C++ STL.… Read More

cpp-set

STL

subset

Arrays

Combinatorial

DSA

Check if there exists a non adjacent pair with given sum

Given an array nums[ ] and an integer target. Find whether there exists a combination of integers in nums[ ] such that their sum is… Read More

Geeks-Premier-League-2022

Arrays

Combinatorial

DSA

Dynamic Programming

Geeks Premier League

Minimal distance such that for every customer there is at least one vendor at given distance

Given N and M number of points on the straight line, denoting the positions of the customers and vendors respectively. Each vendor provides service to… Read More

two-pointer-algorithm

Combinatorial

DSA

Greedy

Mathematical

Maximum count of pairs such that element at each index i is included in i pairs

Given an array arr[] and an integer N, the task is to find the maximum number of pairs that can be formed such that ith… Read More

Algo-Geek 2021

priority-queue

Algo Geek

Arrays

Combinatorial

DSA

Greedy

Queue

Find the Longest Common Subsequence (LCS) in given K permutations

Given K permutations of numbers from 1 to N in a 2D array arr[][]. The task is to find the longest common subsequence of these… Read More

LCS

permutation

Arrays

Combinatorial

DSA

Mathematical

Matrix

Pattern Searching

Maximize product of integers formed by splitting digits of N into two parts in any permutation

Given an integer N in the range [0, 109], the task is to find the maximum product of two integers that are formed by dividing… Read More

number-digits

permutation

Combinatorial

DSA

Mathematical

Misc

Count of possible unique arrays after swapping elements at same index of given Arrays

Given two arrays arr1[] and arr2[] with distinct elements of size N.The task is to count the total number of possible combinations after swapping elements… Read More

Arrays

Combinatorial

DSA

Hash

Count of Binary Strings of length at most N with set bit count as multiple of K

Given two integers N and K, the task is to find the count of binary strings of at most N length that can be formed… Read More

binary-string

setBitCount

Bit Magic

Combinatorial

DSA

Dynamic Programming

Strings