5 Easy LeetCode questions to start competitive-coding

These are 5 LeetCode questions which boost my confidence to start competitive programming and there can be many easy ones out, but I started with these. I provided my Python solutions to the problems, these solutions can be optimized too, just sharing my approach :)

1. FizzBuzz

class Solution:
    def fizzBuzz(self, n: int) -> List[str]:
        l=[]
        for i in range(1,n+1):
            if i%3==0 and i%5==0:
                l.append("FizzBuzz")
            elif i%3==0:
                l.append("Fizz")
            elif i%5==0:
                l.append("Buzz")
            else:
                l.append(str(i))
        return l

2. Single Number

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        return 2*sum(set(nums))-sum(nums)

3. Intersection of two arrays

class Solution:
    def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
        return set(nums1).intersection(set(nums2))

4. Fibonacci Number

class Solution:
    def fib(self, n: int) -> int:
        m=0
        if n==0:
            return 0
        elif n==1:
            return 1
        else:
            m=self.fib(n-1)+self.fib(n-2)
            return m

5. Array Partition-I

class Solution:
    def arrayPairSum(self, nums: List[int]) -> int:
        nums.sort()
        return sum(nums[::2])

Just make sure to start your journey no matter if you're a beginner or pro. I just started off and I can definitely feel the difference, be it in my problem-solving ways or maintaining consistency. Hope this article helps!!

Top comments (2)

bonds • Sep 24 '21

Totally agree. I feel and see a big difference just in the 4 weeks that I have been Leetcoding.
In fact, I just made the same comment in my Leetcode Diary (the Week 4 video is not yet out... too busy coding...little time to blog about the coding).

Anyway, I was working on dissecting problem 21, merging 2 sorted linked list. Leetcode helped me to see how rusty I was. I spent a week on that one problem trying to really hammer out my weaknesses. I feel sooo much better about linked lists (creation, insertion, deletion, traversing). Before problem 21, linked lists terrified me. Now I'm barely shaken by them.

I'm not a star coder yet but I'm also not a scared little kid when it comes to arrays and linked lists.

Leetcode Diary: youtube.com/playlist?list=PLctj_N-...