The Tech Street

package practice; /* Hacker Rank - 2D Array - HourGlass Problem   * Problem Statement - https://www.hackerrank.com/challenges/2d-array  */ import java.util.*; import java.io.*; public class HourGlass { public static void main(String[] args) { // TODO Auto-generated method stub int a[][]  = new int[6][6]; Scanner in = new Scanner(System.in); int temp_sum,sum = -1000000; //Read 2D Matrix-Array  for(int i = 0; i < 6; i++) { for (int j =0; j < 6;j++) { a[i][j] = in.nextInt(); } }                //Compute the sum of 3*3 sub matrix for(int i = 0; i < 6; i++) { for (int j =0; j < 6;j++) { if(j+2 < 6 && i+2 < 6) { temp_sum = a[i][j] + a[i][j+1] + a[i][j+2] + a[i+1][j+1] + a[i+2][j] + a[i+2][j+1] + a[i+2][j+2]; if (temp_sum >= sum) { sum = temp_sum; } } } } System.out.println("Sum:" + sum); } }

package practice; /* Hacker Rank - Read Integer Array and reverse it -https://www.hackerrank.com/challenges/arrays-ds */ import java.util.*; import java.io.*; public class ReverseArray {         public static void main(String[] args) {                 Scanner in = new Scanner(System.in);                 ArrayList<Integer> elements = new ArrayList<Integer>();                 /* Read the SIZE n elements into Array */                 int size = in.nextInt();                 for (int i = 0; i < size;i++) {                         elements.add(in.nextInt());                 }                 /* Collection Method to Reverse */                 Collections.reverse(elements);                 for(int i:elements) {                         System.out.print(i + " ");                 }         }

package practice; import java.util.*; /* Java Program to sort Hashmap */ public class HashSort { public static void main(String[] args) { // TODO Auto-generated method stub HashMap <String,Integer> hm = new HashMap<String,Integer>(); hm.put("Suri",10); hm.put("Sam", 01); hm.put("Abhi", 10); //Put the keys into ArrayList and sort it Set <String> keys = hm.keySet(); ArrayList <String> list = new ArrayList<String>(); list.addAll(keys); //Call sort method from Collections Collections.sort(list); //Display Sorted Key's with Values for (String key:list) { System.out.println(key + ":" + hm.get(key)); } } }

package practice; import java.util.*; /* Collection - Arrays/Linked List/Hash Set's/Hash Map */ public class DemoCollection { public static void main(String [] args) { //ArrayList List<String> a1 = new ArrayList<String>(); a1.add("Surendra"); a1.add("Sam"); a1.add("Steven"); a1.add("sam"); System.out.println("Array list "); System.out.print("\t lenghth:" + a1.size()+ a1); //Linkedlist List <String> l1 = new LinkedList<String>(); l1.add("Suri"); l1.add("Sami"); l1.add("Stevie"); l1.add("Suri"); System.out.println(); System.out.println("Linked List"); System.out.print("\t"+l1); //HashSet's Set <Integer> s1 = new HashSet<Integer>(); s1.add(10); s1.add(20); System.out.println(); System.out.println("Hash Set"); System.out.print("\t"+s1); //H

Java Program to Convert 12HR time to 24HR  Problem - Hacker Rank - https://www.hackerrank.com/challenges/time-conversion import java.io.*; import java.util.*; import java.lang.Object; public class TimeConversion {         /**          * @param args          */ public static void main(String[] args) {         /* Read The time */         Scanner in = new Scanner(System.in);         String input_time = in.next();         //Parse the input         String [] tm = input_time.split(":");         //Extract hh and SS to char array to process AM/PM         int hh = Integer.valueOf(tm[0]);                         char[] secs_str = tm[2].toCharArray();         //AM/PM Time Convertion         if((secs_str[2] == 'A') && (hh == 12))          {                 hh=00;         }          else if((secs_str[2] == 'P') && (hh == 12))         {                 hh=12;         }         else if((secs_str[2] == 'P') &&