HACKERRANK - INTERVIEW PREP KIT- SOLUTIONS IN CPP

HACKERRANK INTERVIEW PREP KIT SOLUTIONS-

* WARM-UP CHALLEGES-

COUNTING VALLEYS

PROBLEM

* DATA STRUCTURES

ARRAY

LINKED LIST

STACK

QUEUE

 HACKERRANK - CRACKING THE CODING INTERVIEW TUTORIALS SOLUTIONS IN CPP

HASH TABLES - RANSOM NOTE

PROBLEM

Complete the checkMagazine function in the editor below. It must print  if the note can be formed using the magazine, or .

checkMagazine has the following parameters:

• string magazine[m]: the words in the magazine
• string note[n]: the words in the ransom note

Prints

• string: either  or , no return value is expected

Input Format

The first line contains two space-separated integers,  and , the numbers of words in the  and the , respectively.
The second line contains  space-separated strings, each .
The third line contains  space-separated strings, each .

Constraints

• .
• Each word consists of English alphabetic letters (i.e.,  to  and  to ).

Sample Input 0

6 4
give me one grand today night
give one grand today

Sample Output 0

Yes

MY SOLUTION-

void checkMagazine(vector<string> magazine, vector<string> note) {
    //Simple finding in the string magazine - passes some test cases
    // for(int i = 0; i < note.size();){
    //     if(find(magazine.begin()+i, magazine.end(), note[i]) != magazine.end())
    //         i++;
    //     else{
    //         cout << "No" <<"\n";
    //         return;
    //     }    
    // }
    // cout << "Yes" <<"\n";
//Hashing in Strings
    unordered_map<string, int>words;
    
    for(auto &it: magazine){ //N words
        words[it]++;
    }
    
    for(auto &it : note){// M words
        if(words[it]> 0){
            words[it]--;
        }
        else{
            cout << "No" <<"\n";
            return;
        }
    }
    cout << "Yes" <<"\n";
    return;
}
TC = O(N+M)

HACKERRANK SOLUTIONS - INTERVIEW PREPARATION KIT - ARRAY - IN C++

  HACKERRANK SOLUTIONS - INTERVIEW PREPARATION KIT - IN C++

ARRAY

1. 2D ARRAY DS

https://www.hackerrank.com/challenges/2d-array/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=arrays

min sum = -9*7 as there are 7 values in 1 hourglass

int hourglassSum(vector<vector<int>> arr) {

    int row = arr.size();

    int col = arr[0].size();

    int max_sum = -63, sum = 0;

    for(int i = 0; i < row-2; i++){

        for(int j = 0; j < col-2; j++){

            sum = arr[i][j] + arr[i][j+1] + 

                arr[i][j+2] + arr[i+1][j+1] + 

                arr[i+2][j] + arr[i+2][j+1] + 

                arr[i+2][j+2];

            if(sum > max_sum)

                max_sum = sum;

        }

    }

    return max_sum;

}

2. LEFT ROTATION

https://www.hackerrank.com/challenges/ctci-array-left-rotation/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=arrays

vector<int> rotLeft(vector<int> a, int d) {

    for(int j = 0; j < d; j++){

        //rotate left by 1

        int temp = a[0];

        int n = a.size();

        for(int i = 0; i < n-1; i++){

            a[i] = a[i+1];

        }

        a[n-1] = temp;

    }

    return a;

}

HACKERRANK SOLUTIONS - INTERVIEW PREPARATION KIT WARM -UP CHALLENGES - IN C++

 HACKERRANK SOLUTIONS - INTERVIEW PREPARATION KIT - IN C++

WARM-UP CHALLENGES

1. SALES BY MATCH

https://www.hackerrank.com/challenges/sock-merchant/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=warmup

Solution - 1:

Algo-

Sort array in increasing/ decreasing order

Compare adjacent sock colors - if equal increase count of a pair, and also increment index, so as to not a sock twice (and count 2 pairs of 3 socks)

TC = O(nlogn+n) = O(nlogn)

int sockMerchant(int n, vector<int> ar) {

    sort(ar.begin(), ar.end());

    int cnt_pair = 0;

    for(int i = 0; i < ar.size() - 1; i++){

        if(ar[i] == ar[i+1]){

            cnt_pair++;

            i++;

        }

    }

    return cnt_pair;

}

2. COUNTING VALLEYS

https://www.hackerrank.com/challenges/counting-valleys/problem?h_l=interview&playlist_slugs%5B%5D%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D%5B%5D=warmup&h_r=next-challenge&h_v=zen