Category Archives: Algorithms & Data structures

Algorithms and data structures.

C++: Unordered maps and sets for non-primitive types

Posted on June 11, 2022 by rendon

Since C++ 11, we can use unordered sets and unordered maps. However, these data structures only seem to work with primitive types and strings. If you need a pair or a vector as the key, you’re out of luck. Fortunately, … Continue reading →

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QuickSelect

Posted on June 11, 2022 by rendon

Theory Quickselect on Wikipedia Implementation in C++ Practice https://leetcode.com/problems/kth-largest-element-in-an-array/

Posted in Algorithms & Data structures, Posts, SoftwareEngineering | 14 Comments

Fenwick tree (aka Binary Indexed Tree)

Posted on May 30, 2022 by rendon

Theory TopCoder – Binary Indexed Trees Algorithms Live – Fenwick tree Wikipedia – Fenwick tree Implementation in C++ Practice Kattis – Movie collection AtCoder – B Fenwick Tree

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Disjoint Set Union (aka Union-Find)

Posted on May 30, 2022 by rendon

Theory Algorithms, 4th edition by Robert Sedgewick, Kevin Wayne 1.5   Case Study: Union-Find Union Find on Cubits.ai Implementation in C++ Practice https://atcoder.jp/contests/practice2/tasks/practice2_a

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Isolate the rightmost (least-significant) bit

Posted on March 27, 2022 by rendon

Fast & elegant: Tests Output Brute force Output for the new version Practice 231. Power of Two 191. Number of 1 Bits Related concepts Two’s complement

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Kadane’s algorithm

Posted on March 13, 2022 by rendon

I just learned about this algorithm, which is considered a dynamic programming approach. However, depending on the implementation, it might not resemble dynamic programming at all. Check out the implementation presented on Wikipedia: That does not look like dynamic programming … Continue reading →

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Interesting programming problems

Posted on February 21, 2021 by rendon

The following problems were either difficult to solve, provided a valuable learning, or both. I’m putting them here so as not to forget a bout them. Drinks Three Pairwise Maximums FashionabLee Captain Flint and Crew Recruitment

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Algorithms live, Episode 0 – Notes

Posted on January 24, 2019 by rendon

One of my goals this year is to catch up with Algorithms Live and as part of that, I’ll be posting my notes for each episode and possibly the solutions to the proposed problems. Episode https://www.youtube.com/watch?v=kPaJfAUwViYSorry, as of now I … Continue reading →

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My C++ template for programming puzzles

Posted on December 3, 2018 by rendon
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