DSA
Day 1 of DSA Daily: Exploring Basic Concepts

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Day 1 of DSA Daily: Exploring Basic Concepts

JAY CHAVAN's photo
JAY CHAVAN
·

3 min read

Today was my first day into my daily Data Structures and Algorithms (DSA) series and below is my progress for today.

I went through the fifth video in Babar's DSA Playlist. You can check out the video here: Babar's DSA Playlist - Video 5. It covered several fundamental concepts.

Firstly, I revisited the basics of bitwise operators. Although I've used them before, it felt beneficial to refresh my understanding. Then, I went deeper into increment and decrement operations. Below is the code that I used just for the clarification:

#include<iostream>
using namespace std;
int main(){
    int a = 4;
    int b = 6;
    //Bitwise Operators
    cout<<"a&b "<< (a&b) << endl;
    cout<<"a|b "<< (a|b) << endl;
    cout<<"~a "<< (~a) << endl;
    cout<<"a^b "<< (a^b) << endl;
    //Left shift 
    cout<<"19<<1 "<<(19<<1)<< endl;
    cout<<"19<<2 "<<(19<<2)<< endl;

    //Right shift 
    cout<<"19>>1 "<<(19>>1)<< endl;
    cout<<"19>>2 "<<(19>>2)<< endl;
    int i = 12;
    //Pre increment ++i (i will change to 13)
    cout<<(++i)<<endl;
    //Post increment i++ (i is 13 and will change to 14 but print 13)
    cout<<(i++)<<endl;
    //Pre decrement --i (i is 14 and will change to 13)
    cout<<(--i)<<endl;
    //Pre decrement i-- (i is 13 will change to 12 but print 13)
    cout<<(i--)<<endl;
}

After that, I focused on the concept of 'for' loops. I knew how to use them, but it was great to solve a few basic problems like finding Fibonacci numbers, calculating sums, checking for prime numbers, etc. Below are the code snippets for the questions.

//Fibonacci
#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    int a = 0;
    int b = 1;
    cout<<a<<" "<<b<<" ";
    for(int i=1;i<=n;i++){
        int nextNum= a+b;
        cout<<nextNum<<" ";
        a = b;
        b = nextNum;
    }
}

//One to n sum
#include<iostream>
using namespace std;
int main(){
    int n;
    cout<<"Enter a number "<<endl;
    cin>>n;
    int sum = 0;
    for(int i=1;i<=n;i++){
        sum+=i;
    }
    cout<<"The sum of 1 to "<<n<<" is "<<sum<<endl;
}

//Prime or Not Prime
#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    bool isPrime = 1;
    for(int i = 2;i<n;i++){
        if(n%i == 0){
            isPrime=0;
            break;
        }
    }
    if(isPrime==0){
        cout<<"It is a Non prime Number";
    }else{
        cout<<"It is a Prime Number";
    }
}

Later, I learned about 'break' and 'continue' statements along with variable scoping. and then ended the day by attempting two problems on LeetCode:

  1. Subtract the Product and Sum of Digits of an Integer I successfully solved this one independently without needing to refer to any external resources.

     class Solution {
 public:
     int subtractProductAndSum(int n) {

         int a = n;
         int sum=0,product=1;
         while(a!=0){
             int digit=a%10;
             product*=digit;
             sum+=digit;
             a=a/10;
         }    
         return product-sum;
     }
 };

  2. Number of 1 Bits I almost completed this by myself but needed a little help towards the end.

     class Solution {
 public:
     int hammingWeight(uint32_t n) {
         int count = 0;
         while(n!=0){
             if(n&1){
                 count++;
             }
             n=n>>1;
         }
         return count;
     }
 };

If you're interested, you can check out my LeetCode profile here to see the problems I've been working on.

That wraps up my progress for today! Tomorrow, I wish to complete another video from the series and solve more problems.

Cheers,
Jay Chavan.

DSAC++