Algorithms

How to find how many characters are repeating in a string. @Test void anotherQ() { // Q1 -- given a String like aaabbbcccaa need to return output like a3b3c3a2. String input = "aaabbbcccazzdddxx"; char[] arr = input.toCharArray(); for (int i = 0; i < arr.length; i++) { char c = arr[i]; int charCounter = 1; System.out.print(c); while (i + 1 < arr.length && c == arr[i + 1]) { charCounter++; i++; } System.out.print(charCounter); } System.out.println("\n" + transformString(input)); } public static String transformString(String input) { if (input == null || input.isEmpty()) { return input; } StringBuilder result = new StringBuilder(); int count = 1; char currentChar = input.charAt(0); for (int i = 1; i < input.length(); i++) { char c = input.charAt(i); if (c == currentChar) { count++; } else { result.append(currentChar).append(count); count = 1; currentChar = c; } } result.append(currentChar).append(count); return result.toString(); } The output is “a3b3c3a1z2d3x2” find the working code here for full working example. ...

Turn an array clockwise therefore the last element comes to first and all hops to right. And counterclockwise meaning last element comes to first and others hops to their left. import java.io.IOException; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; public class Solution { public static void main(String[] args) throws IOException { int[] arr = new int[]{1, 3, 5, 7, 9}; int K = 3; turnTheArrayToRight(arr, K); System.out.println("-----------"); turnTheArrayToLeft(arr, K); System.out.println("-----------"); // no need to reinvent the wheel. List l = new ArrayList<>(); Arrays.stream(arr).forEach(i->l.add(i)); Collections.rotate(l, K); // rotate right System.out.println(Arrays.toString(l.toArray())); Collections.rotate(l, -1 * K); // rotate left System.out.println(Arrays.toString(l.toArray())); } private static int[] turnTheArrayToRight(int[] nums, int k) { for (int j = 0; j < k; j++) { for (int i = nums.length - 1; 0 < i; i--) { int temp = nums[i - 1]; nums[i - 1] = nums[i]; nums[i] = temp; } System.out.println(Arrays.toString(nums)); } return nums; } private static int[] turnTheArrayToLeft(int[] nums, int k) { for (int j = 0; j < k; j++) { for (int i = 0; i < nums.length - 1; i++) { int temp = nums[i]; nums[i] = nums[i + 1]; nums[i + 1] = temp; } System.out.println(Arrays.toString(nums)); } return nums; } } Output ...

Create a class that populates a table represented in the following way. You can think of this as a nested hash/map/dictionary structure. { "row1": { "col1":"foo", "col2":"bar" }, "row2": { "col1":"baz" } } The class should support the following methods: createRow(rowName): Creates a new empty row of the givenname. Do nothing if a row with that name already exists deleteRow(rowName): Deletes a row with the given name. Donothing if a row with that name doesn’t exist updateCell(rowName, columnName, newVal): Sets the value ofthe cell at the given row/column coordinate to the new value. If the row doesnot exist, do nothing. These actions are grouped together in transactions. Theactions above can only be performed as part of a transaction. The class should also support the following methods: ...

The Problem Write a program to search a movie title using screen keyboard with minimal traversal (e.g. Searching for a title Using ROKU/Apple TV remote on Netflix). Input keyboard can have all the characters in any order. Given : Movie title and initial position of remote selection We have five buttons in remote: UP, DOWN, LEFT, RIGHT, OK Keyboard: Input remote could be like this (as it buttons could be in any order) A B C D E F G H I J K L M N O P Q R S T U V W X Y Z For Example: Initial position of remote: A Movie title: BHE Result: RIGHT, OK, RIGHT, DOWN, OK, RIGHT, RIGTH, UP, OK (Right answer) Result: RIGHT, RIGHT, LEFT, OK, RIGHT, DOWN, OK, RIGHT, RIGTH, UP, OK (incorrect, not the shortest one) this problem can be categorized as a grid navigation or grid traversal problem ...