# Day 2 of 90: HFT Prep – Memory Alignment & Binary Search Variants

## **The Mission & Philosophy**

[Watch Day 2 on Youtube here](https://youtu.be/QfMksoek_EI?si=zhAYqug52hE8Z2rn)

I’ve officially kicked off a 90-day challenge to break into top HFT firms like **Graviton**, **Tower Research**, and **Jane Street**. My goal isn't content creation; it’s about maintaining discipline and improving my ability to explain complex code—a critical skill for high-stakes interviews. I’m keeping it raw: no editing, no flashy setups, just engineering focus.

**Finding Signal in the Noise**

* **The Environment**: I'm recording this with a *Bhagavad Gita* path happening right outside my house—it's very loud, but the work doesn't stop.
    
* **The "Rubber Duck"**: Meet **Mr. Pangu**, my penguin interviewer who helps me talk through logic when I get stuck.
    
* **The Tech**: Running **Fedora Linux** with Hyperland on an Asus TUF gaming laptop. I’m an engineer first, so I’m using my built-in webcam to avoid wasting time on production.
    

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### Technical Deep Dive: C++ for High Performance

**1\. Struct Padding & Memory Alignment**

I implemented a `MarketOrder` struct to demonstrate why memory layout is critical in high-frequency trading.

* **The Discovery**: A struct with a `double`, `int`, `char`, and `bool` might seem like 14 bytes, but my system showed **16 bytes**.
    
* **The Logic**: On a 64-bit system, the compiler adds **padding** to ensure data is aligned to 8-byte boundaries.
    
* **The Optimization**: By reordering members to put the largest types first, I reduced a different struct version from **24 bytes to 16 bytes**.
    
* **The HFT Impact**: This saves 8 bytes of memory per order, which can prevent millions of CPU cache misses and reduce the memory footprint by 33%.
    

**2\. Production-Level Coding Standards**

* **No** `bits/stdc++.h`: I'm moving away from competitive programming shortcuts and explicitly including headers like `<iostream>` for cleaner, production-ready code.
    
* **Namespace Discipline**: I've stopped using `using namespace std;` to avoid naming conflicts, which is standard practice in high-performance environments.
    
* **Buffer Management**: Using `\n` instead of `std::endl` to avoid unnecessary buffer flushes, which can be a performance bottleneck.
    

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### DSA: Binary Search Mastery

I tackled two fundamental problems that test precision with boundary conditions:

* **LeetCode 35 (Search Insert Position)**: Implemented binary search using an overflow-safe midpoint calculation: `low + (high - low) / 2`.
    
* **LeetCode 34 (First and Last Position in Sorted Array)**: This involved running binary search logic to find the specific range of a target value in `O(log N)` time.
    

**Current Status**: Day 2/90 Complete.

**Next Steps**: Continuing to strip away "content creator" habits and focus purely on nanosecond-level optimizations.

#HFT #C++ #90DayChallenge #LowLatency #QuantTrading #MAIT