Mastering the Maximum Subarray Problem: Leetcode Medium Problem -Solution with Code

The Rizz Coder
3 min readAug 6, 2023

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Introduction

In this coding problem adventure, we’ll dive into the mysterious world of the Maximum Subarray Problem! 🕵️‍♂️ Imagine being handed an integer array with numbers that hide secrets. Your mission? Uncover the subarray with the largest sum! 🕵️‍♀️

Photo by Antoine Dautry on Unsplash

Intuition

The Intuition 🧠 You may be wondering, “How can I possibly find the subarray with the largest sum?” 🤔 Don’t worry; we’ve got you covered! 🤝 The key to this enigma lies in the exploration of contiguous subarrays. 🌐 We’ll investigate the elements one by one to ensure no hidden treasures escape our grasp! 💎

Kadane’s Algorithm

A Magical Weapon 🗡️ Fear not, for we possess a magical weapon known as Kadane’s Algorithm! 🔮 Named after the brilliant mathematician Jay Kadane, this algorithm is renowned for its simplicity and efficiency. 🧙‍♂️ Kadane’s Algorithm will help us navigate the array’s labyrinth and discover the subarray with the largest sum! 🗝️.

The Approach with Kadane’s Algorithm

We embark on our quest to solve the Maximum Subarray Problem, equipped with the power of Kadane’s Algorithm. Let’s understand how it works its magic! 🎩

As we traverse the array, we’ll initialize two magical variables: “res” and “sum.” ✨

“Res” will hold the maximum sum we seek, while “sum” will act as our compass, guiding us through the array in search of treasure. 🧭

For each element in the array, we add its value to “sum.” 📈 But brace yourself, for here comes the twist: if “sum” ever becomes negative, it means our current subarray isn’t leading us to the hidden riches. 😔 Fear not! Kadane’s Algorithm comes to the rescue! We’ll discard this subarray and start afresh from the next element. 🔄

But wait, there’s more! 🎉 As we continue our exploration, Kadane’s Algorithm ensures that we always keep track of the best “res” we’ve uncovered so far. It might just be the largest sum subarray! 🏴‍☠️

Upon completing our quest, “res” shall reveal the grand treasure — the maximum sum of the subarray we’ve been seeking! 💰

The Dazzling Code 🎇 Are you ready to wield the power of Kadane’s Algorithm and unveil the hidden code? 🧙‍♂️ Behold the secret formula in JavaScript:

/**
* @param {number[]} nums
* @return {number}
*/
var maxSubArray = function(nums) {
// The most negative or minimum number in javascript
let res = Number.NEGATIVE_INFINITY;
let sum = 0;
for(let i=0;i<nums.length;i++)
{
sum = sum + nums[i];
res = Math.max(res, sum);
// If the effective sum till now is negative, ignore the sum and start afresh
if(sum <0)
sum = 0;
}
return res;
};

Conclusion

Congratulations, brave adventurer! 🎉 Armed with Kadane’s Algorithm, you’ve successfully conquered the Maximum Subarray Problem! 🏆 Navigating through the twists and turns of the array, your JavaScript code unveiled the maximum sum subarray — a true triumph! 🎊

Remember, Kadane’s Algorithm is a magical weapon that can conquer large arrays with ease and unveil treasures hidden within. 🗝️ So, keep it handy for future encounters with similar challenges!

Hi, I am the Rizz Coder, Hope you liked my blog post.

🔍 Happy coding, and may your journey be filled with many more captivating coding problems! 🌟

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