Hackerrank Get Node Value problem solution YASH PAL, 31 July 2024 In this HackerRank Get Node Value problem if we have given pointers of the head of a linked list and a specific position, then we need to determine the data value at that position.Problem solution in Python programming.#!/bin/python3 import math import os import random import re import sys class SinglyLinkedListNode: def __init__(self, node_data): self.data = node_data self.next = None class SinglyLinkedList: def __init__(self): self.head = None self.tail = None def insert_node(self, node_data): node = SinglyLinkedListNode(node_data) if not self.head: self.head = node else: self.tail.next = node self.tail = node def print_singly_linked_list(node, sep, fptr): while node: fptr.write(str(node.data)) node = node.next if node: fptr.write(sep) def getNode(head, position): if not head: return None if not head.next: return head.data lst_len = 0 ptr = head while ptr.next: lst_len += 1 ptr = ptr.next while lst_len > position: head = head.next lst_len -= 1 return head.data if __name__ == '__main__': fptr = open(os.environ['OUTPUT_PATH'], 'w') tests = int(input()) for tests_itr in range(tests): llist_count = int(input()) llist = SinglyLinkedList() for _ in range(llist_count): llist_item = int(input()) llist.insert_node(llist_item) position = int(input()) result = getNode(llist.head, position) fptr.write(str(result) + 'n') fptr.close() Problem solution in Java Programming.import java.io.*; import java.math.*; import java.security.*; import java.text.*; import java.util.*; import java.util.concurrent.*; import java.util.regex.*; public class Solution { static class SinglyLinkedListNode { public int data; public SinglyLinkedListNode next; public SinglyLinkedListNode(int nodeData) { this.data = nodeData; this.next = null; } } static class SinglyLinkedList { public SinglyLinkedListNode head; public SinglyLinkedListNode tail; public SinglyLinkedList() { this.head = null; this.tail = null; } public void insertNode(int nodeData) { SinglyLinkedListNode node = new SinglyLinkedListNode(nodeData); if (this.head == null) { this.head = node; } else { this.tail.next = node; } this.tail = node; } } public static void printSinglyLinkedList(SinglyLinkedListNode node, String sep, BufferedWriter bufferedWriter) throws IOException { while (node != null) { bufferedWriter.write(String.valueOf(node.data)); node = node.next; if (node != null) { bufferedWriter.write(sep); } } } static int getNode(SinglyLinkedListNode head, int positionFromTail) { SinglyLinkedListNode fast = head; SinglyLinkedListNode slow = head; int pos = 0; while (pos < positionFromTail) { fast = fast.next; pos++; } while (fast.next!=null) { slow = slow.next; fast = fast.next; } return slow.data; } private static final Scanner scanner = new Scanner(System.in); public static void main(String[] args) throws IOException { BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH"))); int tests = scanner.nextInt(); scanner.skip("(rn|[nru2028u2029u0085])?"); for (int testsItr = 0; testsItr < tests; testsItr++) { SinglyLinkedList llist = new SinglyLinkedList(); int llistCount = scanner.nextInt(); scanner.skip("(rn|[nru2028u2029u0085])?"); for (int i = 0; i < llistCount; i++) { int llistItem = scanner.nextInt(); scanner.skip("(rn|[nru2028u2029u0085])?"); llist.insertNode(llistItem); } int position = scanner.nextInt(); scanner.skip("(rn|[nru2028u2029u0085])?"); int result = getNode(llist.head, position); bufferedWriter.write(String.valueOf(result)); bufferedWriter.newLine(); } bufferedWriter.close(); scanner.close(); } } Problem solution in C++ programming.#include <bits/stdc++.h> using namespace std; class SinglyLinkedListNode { public: int data; SinglyLinkedListNode *next; SinglyLinkedListNode(int node_data) { this->data = node_data; this->next = nullptr; } }; class SinglyLinkedList { public: SinglyLinkedListNode *head; SinglyLinkedListNode *tail; SinglyLinkedList() { this->head = nullptr; this->tail = nullptr; } void insert_node(int node_data) { SinglyLinkedListNode* node = new SinglyLinkedListNode(node_data); if (!this->head) { this->head = node; } else { this->tail->next = node; } this->tail = node; } }; void print_singly_linked_list(SinglyLinkedListNode* node, string sep, ofstream& fout) { while (node) { fout << node->data; node = node->next; if (node) { fout << sep; } } } void free_singly_linked_list(SinglyLinkedListNode* node) { while (node) { SinglyLinkedListNode* temp = node; node = node->next; free(temp); } } int getNode(SinglyLinkedListNode* head, int positionFromTail) { int n = 0; SinglyLinkedListNode *tmp = head; while(tmp) {n++; tmp = tmp->next;} fprintf(stderr, "n: %dn", n); int pos = n - positionFromTail-1; fprintf(stderr, "Pos: %dn", pos); while(pos--){head = head->next;} return head->data; } int main() { ofstream fout(getenv("OUTPUT_PATH")); int tests; cin >> tests; cin.ignore(numeric_limits<streamsize>::max(), 'n'); for (int tests_itr = 0; tests_itr < tests; tests_itr++) { SinglyLinkedList* llist = new SinglyLinkedList(); int llist_count; cin >> llist_count; cin.ignore(numeric_limits<streamsize>::max(), 'n'); for (int i = 0; i < llist_count; i++) { int llist_item; cin >> llist_item; cin.ignore(numeric_limits<streamsize>::max(), 'n'); llist->insert_node(llist_item); } int position; cin >> position; cin.ignore(numeric_limits<streamsize>::max(), 'n'); int result = getNode(llist->head, position); fout << result << "n"; } fout.close(); return 0; } Problem solution in C programming.#include <assert.h> #include <limits.h> #include <math.h> #include <stdbool.h> #include <stddef.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> char* readline(); typedef struct SinglyLinkedListNode SinglyLinkedListNode; typedef struct SinglyLinkedList SinglyLinkedList; struct SinglyLinkedListNode { int data; SinglyLinkedListNode* next; }; struct SinglyLinkedList { SinglyLinkedListNode* head; SinglyLinkedListNode* tail; }; SinglyLinkedListNode* create_singly_linked_list_node(int node_data) { SinglyLinkedListNode* node = malloc(sizeof(SinglyLinkedListNode)); node->data = node_data; node->next = NULL; return node; } void insert_node_into_singly_linked_list(SinglyLinkedList** singly_linked_list, int node_data) { SinglyLinkedListNode* node = create_singly_linked_list_node(node_data); if (!(*singly_linked_list)->head) { (*singly_linked_list)->head = node; } else { (*singly_linked_list)->tail->next = node; } (*singly_linked_list)->tail = node; } void print_singly_linked_list(SinglyLinkedListNode* node, char* sep, FILE* fptr) { while (node) { fprintf(fptr, "%d", node->data); node = node->next; if (node) { fprintf(fptr, "%s", sep); } } } void free_singly_linked_list(SinglyLinkedListNode* node) { while (node) { SinglyLinkedListNode* temp = node; node = node->next; free(temp); } } int getNode( SinglyLinkedListNode* head, int positionFromTail ) { int total = 0; SinglyLinkedListNode* nodePtr = head; // get the number of the total number of node while( nodePtr ) { total++; nodePtr = nodePtr->next; } nodePtr = head; for( int indx = 0; indx < total-positionFromTail-1; indx++ ) { nodePtr = nodePtr->next; } return nodePtr->data; } int main() { FILE* fptr = fopen(getenv("OUTPUT_PATH"), "w"); char* tests_endptr; char* tests_str = readline(); int tests = strtol(tests_str, &tests_endptr, 10); if (tests_endptr == tests_str || *tests_endptr != ' ') { exit(EXIT_FAILURE); } for (int tests_itr = 0; tests_itr < tests; tests_itr++) { SinglyLinkedList* llist = malloc(sizeof(SinglyLinkedList)); llist->head = NULL; llist->tail = NULL; char* llist_count_endptr; char* llist_count_str = readline(); int llist_count = strtol(llist_count_str, &llist_count_endptr, 10); if (llist_count_endptr == llist_count_str || *llist_count_endptr != ' ') { exit(EXIT_FAILURE); } for (int i = 0; i < llist_count; i++) { char* llist_item_endptr; char* llist_item_str = readline(); int llist_item = strtol(llist_item_str, &llist_item_endptr, 10); if (llist_item_endptr == llist_item_str || *llist_item_endptr != ' ') { exit(EXIT_FAILURE); } insert_node_into_singly_linked_list(&llist, llist_item); } char* position_endptr; char* position_str = readline(); int position = strtol(position_str, &position_endptr, 10); if (position_endptr == position_str || *position_endptr != ' ') { exit(EXIT_FAILURE); } int result = getNode(llist->head, position); fprintf(fptr, "%dn", result); } fclose(fptr); return 0; } char* readline() { size_t alloc_length = 1024; size_t data_length = 0; char* data = malloc(alloc_length); while (true) { char* cursor = data + data_length; char* line = fgets(cursor, alloc_length - data_length, stdin); if (!line) { break; } data_length += strlen(cursor); if (data_length < alloc_length - 1 || data[data_length - 1] == 'n') { break; } size_t new_length = alloc_length << 1; data = realloc(data, new_length); if (!data) { break; } alloc_length = new_length; } if (data[data_length - 1] == 'n') { data[data_length - 1] = ' '; } data = realloc(data, data_length); return data; }Problem solution in JavaScript programming.'use strict'; const fs = require('fs'); process.stdin.resume(); process.stdin.setEncoding('utf-8'); let inputString = ''; let currentLine = 0; process.stdin.on('data', inputStdin => { inputString += inputStdin; }); process.stdin.on('end', _ => { inputString = inputString.replace(/s*$/, '') .split('n') .map(str => str.replace(/s*$/, '')); main(); }); function readLine() { return inputString[currentLine++]; } const SinglyLinkedListNode = class { constructor(nodeData) { this.data = nodeData; this.next = null; } }; const SinglyLinkedList = class { constructor() { this.head = null; this.tail = null; } insertNode(nodeData) { const node = new SinglyLinkedListNode(nodeData); if (this.head == null) { this.head = node; } else { this.tail.next = node; } this.tail = node; } }; function printSinglyLinkedList(node, sep, ws) { while (node != null) { ws.write(String(node.data)); node = node.next; if (node != null) { ws.write(sep); } } } function getNode( head, position) { var current = head; var prev var next while(current) { next = current.next; current.next = prev; prev = current; current = next; } for(var i=0;i<position;i++){ prev = prev.next; } return prev.data; } function main() { const ws = fs.createWriteStream(process.env.OUTPUT_PATH); const tests = parseInt(readLine(), 10); for (let testsItr = 0; testsItr < tests; testsItr++) { const llistCount = parseInt(readLine(), 10); let llist = new SinglyLinkedList(); for (let i = 0; i < llistCount; i++) { const llistItem = parseInt(readLine(), 10); llist.insertNode(llistItem); } const position = parseInt(readLine(), 10); let result = getNode(llist.head, position); ws.write(result + "n"); } ws.end(); } coding problems solutions