Four Problems in 10min

-
Challenge was to solve 4 LC problems (2 easy, 2 medium) in <= 10min. I picked the ones below, new ones, from today. Solutions might not be the most elegant and/or efficient, but they all passed. Code is down below, cheers, ACC.



Solution to Problem #1:

    public class Solution
    {
        public int LongestSubarray(int[] nums)
        {
            Hashtable maxOnesAtPosition = new Hashtable();

            bool insideOne = false;
            int beginPos = 0;
            for (int i = 0; i < nums.Length; i++)
            {
                if (nums[i] == 1 && !insideOne)
                {
                    beginPos = i;
                    insideOne = true;
                }
                else if (nums[i] == 0 && insideOne)
                {
                    maxOnesAtPosition.Add(beginPos, i - beginPos);
                    if (i - 1 > beginPos)
                    {
                        maxOnesAtPosition.Add(i - 1, i - beginPos);
                    }
                    insideOne = false;
                }
                
                if (i == nums.Length - 1 && nums[i] == 1)
                {
                    maxOnesAtPosition.Add(beginPos, i - beginPos + 1);
                    if (i > beginPos)
                    {
                        maxOnesAtPosition.Add(i, i - beginPos + 1);
                    }
                }
            }

            bool atLeastOneZero = false;
            int max = 0;
            for (int i = 0; i < nums.Length; i++)
            {
                if (nums[i] == 0)
                {
                    int current = 0;
                    if (maxOnesAtPosition.ContainsKey(i - 1)) current += (int)maxOnesAtPosition[i - 1];
                    if (maxOnesAtPosition.ContainsKey(i + 1)) current += (int)maxOnesAtPosition[i + 1];
                    max = Math.Max(max, current);
                    atLeastOneZero = true;
                }
            }

            if (!atLeastOneZero) return nums.Length - 1;
            return max;
        }
    }

Solution to Problem #2:

    public class Solution
    {
        public int KthFactor(int n, int k)
        {
            int count = 0;

            for (int i = 1; i <= n; i++)
            {
                if (n % i == 0)
                {
                    count++;
                    if (count == k)
                    {
                        return i;
                    }
                }
            }

            return -1;
        }
    }

Solution to Problem #3:

    public class Solution
    {
        public double Average(int[] salary)
        {
            Array.Sort(salary);

            int sum = 0;
            for (int i = 1; i < salary.Length - 1; i++)
            {
                sum += salary[i];
            }

            return (1.0 * sum) / (salary.Length - 2);
        }
    }

Solution to Problem #4:

    public class Solution
    {
        public bool IsPathCrossing(string path)
        {
            Hashtable points = new Hashtable();

            int x = 0;
            int y = 0;
            points.Add(x * 20000 + y, true);
            for (int i = 0; i < path.Length; i++)
            {
                switch (path[i])
                {
                    case 'N':
                        y++;
                        break;
                    case 'S':
                        y--;
                        break;
                    case 'E':
                        x++;
                        break;
                    case 'W':
                        x--;
                        break;
                }

                if (points.ContainsKey(x * 20000 + y)) return true;
                points.Add(x * 20000 + y, true);
            }

            return false;
        }
    }

Comments

Post a Comment

Popular posts from this blog

Golang vs. C#: performance characteristics (simple case study)

-
Image
This is an interesting example to study the performance characteristics of Golang compared to C# for a very particular case (not generalized though).  The same code was written in C# and Golang (literally translated from one to the other). Below you'll be able to see the source code for both. The problem is a simple post-order DFS in a tree-like graph. The code in C# times out (TLE = Time Limited Exceeded). The code in Golang not only works but beats 100% of the other Golang submissions. Take a look the image below: Some potential reasons for the performance gains from Go in this particular example are: 1. Language and Runtime Differences:    Go is compiled directly to machine code, while C# typically runs on a virtual machine (CLR).    Go has a simpler runtime with less overhead compared to the .NET runtime.    Go's garbage collector is designed for low latency, which can lead to better performance in some scenarios. 2. Data Structures:    Go's `map` is generally more effi
Read more

Claude vs ChatGPT: A Coder's Perspective on LLM Performance

-
Image
In the rapidly evolving world of Large Language Models (LLMs), recent releases from OpenAI's ChatGPT have garnered significant attention. However, when it comes to coding tasks, Anthropic's Claude.ai continues to impress me with its speed and quality of output. Benchmarking with LeetCode While LeetCode problems aren't the definitive measure of an AI's coding capabilities (they're pre-designed puzzles, after all), they offer an interesting playground for comparison. Let's dive into a recent example: The Problem K-th Largest Perfect Subtree Size in Binary Tree - LeetCode 3319. K-th Largest Perfect Subtree Size in Binary Tree Medium 36 6 Add to List Share You are given the  root  of a  binary tree  and an integer  k . Return an integer denoting the size of the  k th   largest   perfect binary   subtree , or  -1  if it doesn't exist. A  perfect binary tree  is a tree where all leaves are on the same level, and every parent has two children.   Example 1: Input:  
Read more

My Quickshort interview with Sir Tony Hoare, the inventor of Quicksort

-
If you studied Computer Science, at some point, usually in the beginning of your algorithm courses, you learn about sorting algorithms, the most famous one being Quicksort. Studies show that the most frequent reactions to those who learn about Quicksort for the very first time are: 1) Wow!!! How could anyone possibly come up with that idea? 2) Hmm, explain it to me one more time please? 3) #1 followed by #2, or #2 follower by #1 Not surprisingly I was right there in the #3 category. To learn about Quicksort just Bing it , but this blog post isn't about Quicksort necessarily, but rather about the person who invented it, Sir Tony Hoare . The winner of the Turing Award prize in 1980, Sir Tony Hoare currently works at Microsoft, just like me, and he was kind enough to give me the honor to interview him for my coding blog. Without any further due, here it is - I hope you Quick-enjoy it too! :) [Marcelo De Barros] First, thank you Tony for the incredible opportunity to ask you f
Read more