combinatorics

46 posts

Count Number of Distinct Binary Strings After Applying Flip Operations

Last Updated: 29 May 2024

Given a binary string s and a positive integer k. In a operation you can repeatedly choose any substring of length k in s and flip all its characters (0s to 1s, 1s to 0s)....read more

Ways to arrange N balls of K colors with no adjacent same colors

Last Updated: 23 July 2025

Given infinite balls of K distinct colors. Count the number of ways to arrange N balls in a line such that no two adjacent balls are of same color. Since the answer may be...read more

Binary Exponentiation

Count all ordered pairs (A, B) such that A and B are disjoint

Last Updated: 29 February 2024

Given an array arr[] of size n contains distinct elements, the task is to find the number of ordered pairs (A, B) that can be made where A and B are subsets of the given a...read more

DSA

combinatorics

Geeks Premier League 2023

Count number of pairs of arrays (a, b) such that a[i] <= b[i]

Last Updated: 23 July 2025

Given two integers n and m, the task is to count the number of pairs of arrays (a, b) where both arrays have a length of m, contain integers between 1 and n (inclusive), a...read more

Picked

DSA

combinatorics

Algorithms-Dynamic Programming

Geeks Premier League 2023

Count number of ways array can be partitioned such that same numbers are present in same subarray

Last Updated: 23 July 2025

Given an array A[] of size N. The Task for this problem is to count several ways to partition the given array A[] into continuous subarrays such that the same integers are...read more

Geeks Premier League 2023

Find the number of ways to draw the last colored ball

Last Updated: 23 July 2025

Given an array balls[] representing the count of colored balls labeled from 1 to k, the task is to determine the number of ways to draw the last ball of color i before dra...read more

Picked

DSA

combinatorics

Algorithms-Dynamic Programming

binomial coefficient

Geeks Premier League 2023

Stars and Bars Algorithms for Competitive Programming

Last Updated: 28 May 2026

The Stars and Bars (also known as Balls and Urns) technique is a widely used method in Combinatorics, which is the branch of mathematics dealing with counting and arrangem...read more

Geeks Premier League 2023

Count Weird Triplets

Last Updated: 26 February 2024

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 2 same elements.Examples: Input: A[] = [5, 5, ...read more

Geeks Premier League 2023

Maximize the sum of all people's travel distances

Last Updated: 23 July 2025

Given a group of N people who hate each other such that each of them lives in a different city. The cities are connected by N-1 roads such that road[i] = {u, v, w} indicat...read more

DSA

combinatorics

DFS

Counting City Trips with K Stops

Last Updated: 18 January 2024

Given n cities connected by (n-1) roads, each specified by [a, b, type], denoting a connection between cities a and b of a certain 'type' (0 for normal roads, 1 for highwa...read more

Geeks Premier League 2023

Number of ways to make N using product of M integers

Last Updated: 31 July 2023

Given two integers N (1 = N = 1e9) and M (M = 1e5), the task is to find the number of ways to represent the number N in terms of the product of M integers. Find the answer...read more

Permutation and Combination

binomial coefficient

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

Last Updated: 23 January 2023

Given an array of pairs arr[] of size N (N ? 3) where each element of pair is at most N and each pair is unique, the task is to determine the number of ways to select trip...read more

Count of binary string of length N with at least X 0s and Y 1s

Last Updated: 03 October 2025

Given three numbers N, X, and Y, find the count of unique binary strings of length N having at least X 0s and Y 1s.Examples:Input: N=5, X=1, Y=2Output: 25Input: N=3, X=1, ...read more

Permutation and Combination

Count of subsequences with sum two less than the array sum

Last Updated: 23 July 2025

Given an array vec[] of size N of non-negative integers. The task is to count the number of subsequences with the sum equal to S - 2 where S is the sum of all the elements...read more

DSA

combinatorics

subsequence

Find sum of difference of maximum and minimum over all possible subsets of size K

Last Updated: 23 July 2025

Given an array arr[] of N integers and an integer K, the task is to find the sum of the difference between the maximum and minimum elements over all possible subsets of si...read more

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