prefix-sum

349+ posts

Last Updated: 15 October 2026

Given an array arr[], partition it into four non-empty contiguous subarrays P, Q, R, and S. Let the sums of these subarrays be W, X, Y, and Z, respectively. Find the minim...read more

Last Updated: 05 July 2025

You are given a 2D integer array intervals[][] of length n and integer k, where each intervals[i] = [start, end] represents a closed interval (i.e., all integers from star...read more

Last Updated: 28 July 2025

Given a string s consisting of lowercase English letters, identify all characters whose first and last occurrences are at different positions.For each such character, comp...read more

Top Problems on Prefix Sum Technique for Interviews

Last Updated: 23 July 2025

The Prefix Sum Technique is a powerful and widely used approach in coding interviews, especially for optimizing queries related to subarray sums and cumulative computation...read more

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prefix-sum

CSES Solutions - Forest Queries

Last Updated: 23 July 2025

Given an N X N grid representing the map of a forest. Each square is either empty or contains a tree. The upper-left square has coordinates (1,1), and the lower-right squa...read more

CSES Solutions – Static Range Sum Queries

Last Updated: 23 July 2025

Given an array arr[] of N integers, your task is to process Q queries of the form: what is the sum of values in range [a,b]?ExamplesInput: arr[] = {1, 3, 4, 8, 6, 1, 4, 2}...read more

CSES Solutions - Subarray Sums II

Last Updated: 23 July 2025

Given an array arr[] of N integers, your task is to count the number of subarrays having sum X.Examples: Input: N = 5, X = 7, arr[] = {2, -1, 3, 5, -2}Output: 2Explanation...read more

Find the sum of elements after X deletions and Y sign inversions

Last Updated: 23 July 2025

Two Players A and B are engaged in a game with an array of positive integers arr[] of size N. The game starts with Player A deleting at max X elements from the array arr[]...read more

Maximize number of indices with prefix sum equal to 0

Last Updated: 10 April 2024

Given an array arr[] of size N, you can perform the following operation on the array any number of times: If arr[i]=0, we can replace it with any integer. Your task is to ...read more

Picked

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prefix-sum

Algorithms-Dynamic Programming

Geeks Premier League 2023

Rearrange the given array to minimize the indices with prefix sum at least arr[i]

Last Updated: 23 July 2025

Given an array arr[] consisting of N positive integers, rearrange the array to minimize the number of indices i such that the prefix sum from index 1 to index i-1 is great...read more

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Connect through Content 2023

Minimum number of operations required to make all the elements positive

Last Updated: 04 April 2024

Given an array A[] of length N. You can apply the below operation:Choose an index i such that (i+1) element exists. After that choose any number X (positive or negative). ...read more

CPP-Competitive-Programming

DSA-Blogs

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Queries to find number of indexes where characters repeated twice in row in substring L to R

Last Updated: 23 July 2025

Given string S of size N consisting of lower case characters and 2d array Q[][2] of size M representing several queries of type {L, R} representing a range. The task for ...read more

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Queries to find Maximum index R with bitwise AND from index L at least K

Last Updated: 23 July 2025

Given array A[] of size N and array Q[][2] of size M representing queries of the type {L, K}. The task for this problem is to answer queries for each query to find the lar...read more

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Minimize the Sum of Absolute Costs of an Array Optimally

Last Updated: 18 January 2024

Given an array arr[] of costs, your task is to minimize the sum of the absolute differences between consecutive costs by performing following operation at most once. Opera...read more

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prefix-sum

math

Data Structures-Array

suffix-sum

Bitwise OR Triplets in a Binary String

Last Updated: 23 July 2025

Given a binary string S of length N, where S[i] represents an integer value. the task is to count the number of ways to choose three different indices ( 0 = i j k N) su...read more

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