--- title: "#dsa-challenge articles | Hashnode" description: "Explore 3 articles tagged #dsa-challenge on Hashnode. Tutorials, guides, and how-tos from the community." url: "https://hashnode.com/tag/dsa-challenge" --- Tag # #dsa-challenge 3 posts · 0 followers [Sakshi Sharma](https://hashnode.com/@SakshiSharma45) · [Oct 3, 2025](https://hashnode.com/posts/prefix-sum-4/68dfb54c4c6b22043021b649) ### [Prefix Sum - 4](https://prefix-sum.hashnode.dev/prefix-sum-4?utm_source=hashnode&utm_medium=feed) LeetCode 724: Find Pivot Index – A Mathematical Prefix Sum Problem We’ve been solving prefix sum questions, and this one — Find Pivot Index — is actually more about mathematics than coding tricks. The problem says: Find an index where the sum of all... 3 min read · [prefix-sum.hashnode.dev](https://prefix-sum.hashnode.dev/prefix-sum-4?utm_source=hashnode&utm_medium=feed) [Sakshi Sharma](https://hashnode.com/@SakshiSharma45) · [Oct 2, 2025](https://hashnode.com/posts/prefix-sum-3/68de7fec82bb60c523bea91a) ### [Prefix Sum -3](https://prefix-sum.hashnode.dev/prefix-sum-3?utm_source=hashnode&utm_medium=feed) Subarray Sum Equals K (Leetcode 560) – From Brute Force to HashMap When I saw this problem for the first time, honestly my mind just went:“Okay… subarray sum… let’s check all subarrays!” 😅That’s the brute force approach. Later I found the prefix sum... 3 min read · [prefix-sum.hashnode.dev](https://prefix-sum.hashnode.dev/prefix-sum-3?utm_source=hashnode&utm_medium=feed) [Anoushka Singh](https://hashnode.com/@ans-data-codes) · [Jun 8, 2025](https://hashnode.com/posts/so-uhh-what-even-is-this/68458c8a402e93abf3d095b5) ### [So Uhh, What Even is This?](https://ans-data-codes.hashnode.dev/so-uhh-what-even-is-this?utm_source=hashnode&utm_medium=feed) a.k.a an intro no one asked for, but here I am anyway. 3 min read · [ans-data-codes.hashnode.dev](https://ans-data-codes.hashnode.dev/so-uhh-what-even-is-this?utm_source=hashnode&utm_medium=feed) [1](https://hashnode.com/posts/so-uhh-what-even-is-this/68458c8a402e93abf3d095b5)