HackerRank Solutions: Mastering Coding Challenges

hackerrank solutions

HackerRank Solutions

HackerRank solution refers to a program or code snippet written to solve a specific problem on the HackerRank platform. HackerRank is a popular online coding platform that offers a variety of programming challenges, coding competitions, and interview preparation material.

When referring to a HackerRank solution it typically means a solution to a coding problem available on the HackerRank website. These solutions are often written in various programming languages, including Java, Python, C++, and others, depending on the user’s preference and the requirements of the problem.

A typical HackerRank solution includes the following components:

  1. Problem Statement: A description of the problem to be solved, including input specifications, output specifications, and any constraints or requirements.
  2. Solution Code: The actual code written to solve the problem. This code should implement the logic necessary to solve the problem efficiently and correctly.
  3. Test Cases: A set of sample input-output pairs used to test the correctness of the solution code. These test cases help ensure that the solution produces the expected output for different input scenarios.
  4. Explanation or Comments: Optional explanations or comments within the code to clarify the logic, approach, or any specific details about the solution.

When submitting a HackerRank solution, it is essential to ensure that the code is correct, efficient, and well-documented. Additionally, the solution should adhere to any specific requirements or constraints specified in the problem statement. HackerRank provides an interactive coding environment where users can write, compile, and test their code before submitting it for evaluation.

Diagonal difference hackerrank solution

Here is a Java solution to the “Diagonal Difference” problem on HackerRank:

import java.util.Scanner;

public class DiagonalDifference {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // Read the size of the square matrix
        int n = scanner.nextInt();

        // Initialize variables to store the sums of the diagonals
        int primaryDiagonalSum = 0;
        int secondaryDiagonalSum = 0;

        // Iterate through the elements of the matrix
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                int num = scanner.nextInt();
                // Add the element to the primary diagonal sum if i == j
                if (i == j) {
                    primaryDiagonalSum += num;
                }
                // Add the element to the secondary diagonal sum if i + j == n - 1
                if (i + j == n - 1) {
                    secondaryDiagonalSum += num;
                }
            }
        }

        // Calculate the absolute difference between the sums of the diagonals
        int diagonalDifference = Math.abs(primaryDiagonalSum - secondaryDiagonalSum);

        // Output the result
        System.out.println(diagonalDifference);

        // Close the scanner
        scanner.close();
    }
}

This solution reads an integer n representing the size of the square matrix, followed by the elements of the matrix. It then calculates the sum of the elements on the primary diagonal (where the row index equals the column index) and the sum of the elements on the secondary diagonal (where the sum of the row and column indices equals n - 1). Finally, it calculates the absolute difference between the sums of the diagonals and prints the result.

Dynamic array in c hackerrank solution

Here’s a solution to the “Dynamic Array” problem on HackerRank using C:

#include <stdio.h>
#include <stdlib.h>

int main() {
    int n, q;
    scanf("%d %d", &n, &q);

    // Create an array of n empty sequences (lists)
    int** sequences = (int**)malloc(n * sizeof(int*));
    int* lastAnswers = (int*)calloc(n, sizeof(int));

    // Process the queries
    int lastAnswer = 0;
    for (int i = 0; i < q; i++) {
        int query, x, y;
        scanf("%d %d %d", &query, &x, &y);

        // Find the sequence corresponding to query 1 or 2
        int index = (x ^ lastAnswer) % n;
        int* sequence = sequences[index];

        // Process the query
        if (query == 1) {
            // Append element y to the sequence
            if (sequence == NULL) {
                sequence = (int*)malloc(sizeof(int));
                sequences[index] = sequence;
            } else {
                sequence = (int*)realloc(sequence, (lastAnswers[index] + 1) * sizeof(int));
            }
            sequence[lastAnswers[index]] = y;
            lastAnswers[index]++;
        } else if (query == 2) {
            // Print the value of element y % size of the sequence
            lastAnswer = sequence[y % lastAnswers[index]];
            printf("%d\n", lastAnswer);
        }
    }

    // Free dynamically allocated memory
    for (int i = 0; i < n; i++) {
        free(sequences[i]);
    }
    free(sequences);
    free(lastAnswers);

    return 0;
}

This solution reads two integers n and q representing the number of sequences and the number of queries, respectively. It then processes each query, which can be of two types:

  1. Query 1: Append the integer y to the xth sequence.
  2. Query 2: Print the value of the element at index y % size of the sequence in the xth sequence, and update the lastAnswer variable.

The solution uses dynamic memory allocation to create and resize sequences as needed. Additionally, it utilizes the XOR operation to determine the index of the sequence to operate on, based on the query parameters and the last answer. Finally, it frees all dynamically allocated memory before exiting the program.

Time conversion hackerrank solution

Here’s a solution to the “Time Conversion” problem on HackerRank using C:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
    char time[11];
    scanf("%s", time);

    // Extract hours, minutes, and seconds
    int hours, minutes, seconds;
    sscanf(time, "%d:%d:%d", &hours, &minutes, &seconds);

    // Check if it's PM and adjust hours accordingly
    if (strstr(time, "PM") != NULL && hours != 12) {
        hours += 12;
    }
    // Check if it's AM and adjust hours accordingly
    else if (strstr(time, "AM") != NULL && hours == 12) {
        hours = 0;
    }

    // Print the time in 24-hour format (hh:mm:ss)
    printf("%02d:%02d:%02d\n", hours, minutes, seconds);

    return 0;
}

This solution reads a string representing the time in 12-hour format (e.g., “07:05:45PM”) and converts it to 24-hour format. It extracts the hours, minutes, and seconds using sscanf(), then checks if it’s PM and adjusts the hours accordingly by adding 12 if the current hour is not 12. If it’s AM and the hour is 12, it sets the hour to 0. Finally, it prints the time in 24-hour format using printf() with formatting %02d to ensure that the hours, minutes, and seconds are printed with leading zeros if needed.

Compare the triplets hackerrank solution

Here’s a solution to the “Compare the Triplets” problem on HackerRank using C:

#include <stdio.h>

int main() {
    int alice[3], bob[3];
    int alicePoints = 0, bobPoints = 0;

    // Read Alice's scores
    scanf("%d %d %d", &alice[0], &alice[1], &alice[2]);

    // Read Bob's scores
    scanf("%d %d %d", &bob[0], &bob[1], &bob[2]);

    // Compare scores and update points
    for (int i = 0; i < 3; i++) {
        if (alice[i] > bob[i]) {
            alicePoints++;
        } else if (alice[i] < bob[i]) {
            bobPoints++;
        }
    }

    // Print the final scores
    printf("%d %d\n", alicePoints, bobPoints);

    return 0;
}

This solution reads two arrays representing the scores of Alice and Bob for three different categories. It then iterates through each category, compares the scores of Alice and Bob, and updates their points accordingly. Finally, it prints the final scores of Alice and Bob.

Conclusions

Conclusions on HackerRank Solutions:

  1. Problem-Solving Skills: Solving problems on HackerRank improves problem-solving skills by providing a wide range of challenges across different domains such as algorithms, data structures, mathematics, and more. These challenges often require creative thinking and algorithmic approaches to devise efficient solutions.
  2. Coding Proficiency: Writing solutions to HackerRank problems enhances coding proficiency in various programming languages like C, Java, Python, and others. It helps in learning language-specific features, syntax, and best practices, thereby improving overall coding skills.
  3. Algorithmic Understanding: HackerRank problems are designed to test understanding and implementation of fundamental algorithms and data structures. By solving these problems, individuals gain a deeper understanding of concepts such as sorting, searching, dynamic programming, graph theory, and more.
  4. Optimization Techniques: HackerRank challenges often have constraints regarding time and space complexity. As a result, individuals learn optimization techniques to improve the efficiency of their solutions, such as reducing time complexity, minimizing memory usage, and optimizing code execution.
  5. Debugging and Troubleshooting: Solving HackerRank problems involves debugging and troubleshooting code to identify and fix errors. This process enhances skills in error detection, code analysis, and debugging techniques, which are essential for writing robust and error-free code.
  6. Time Management: HackerRank contests and challenges have time limits, encouraging individuals to manage their time effectively while solving problems. This helps in developing time management skills, prioritizing tasks, and efficiently allocating time to different problem-solving stages.
  7. Learning Resources: HackerRank provides editorial solutions, discussions, and community forums where individuals can learn from others’ approaches, share insights, and discuss problem-solving strategies. It serves as a valuable learning resource for beginners and experienced programmers alike.
  8. Preparation for Interviews: HackerRank offers interview preparation kits and mock interviews, simulating real-world interview scenarios. Solving problems on HackerRank prepares individuals for technical interviews by enhancing problem-solving abilities, coding skills, and familiarity with common interview questions.

In conclusion, solving problems on HackerRank is an effective way to enhance coding skills, improve problem-solving abilities, and prepare for technical interviews. It provides a platform for continuous learning, skill development, and collaboration within a global community of programmers and enthusiasts.

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