Leetcode 379: Design Phone Directory

Design a phone directory that initially has maxNumbers empty slots that can store numbers. The directory should store numbers, check if a certain slot is empty or not, and empty a given slot. Implement the PhoneDirectory class: PhoneDirectory(int maxNumbers) Initializes the phone directory with the number of available slots maxNumbers.int get() Provides a number that ...

Leetcode 370: Range Addition

You are given an integer length and array updates where updates[i] = [startIdxi, endIdxi, inci]. You have an array “arr” of length with all zeros, and you have some operation to apply on arr. In the ith operation, you should increment all the elements arr[startIdxi], arr[startIdxi + 1], …, arr[endIdxi] by inci. Return arr after ...

Leetcode 1056: Confusing Number

A confusing number is a number that, when rotated 180 degrees, becomes a different number with each digit valid. We can rotate the digits of a number by 180 degrees to form new digits. When 0, 1, 6, 8, and 9 are rotated 180 degrees, they become 0, 1, 9, 8, and 6, respectively.When 2, ...

Leetcode 290: Word Pattern

Given a pattern and a string s, find if s follows the same pattern. Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in s. https://leetcode.com/problems/word-pattern/ class Solution { public boolean wordPattern(String pattern, String s) { String[] sArr = s.split(" "); Map<Character, String> map = new HashMap<>(); char[] pArr = pattern.toCharArray(); //if the length of ...

Solved! Leetcode 1428: Leftmost Column with at Least a One

A row-sorted binary matrix means that all elements are 0 or 1 and each row of the matrix is sorted in non-decreasing order.Given a row-sorted binary matrix binaryMatrix, return the index (0-indexed) of the leftmost column with a 1 in it. If such an index does not exist, return -1.You can’t access the Binary Matrix ...

Leetcode 797: All Paths From Source to Target

Given a directed acyclic graph (DAG) of n nodes labeled from 0 to n - 1, find all possible paths from node 0 to node n - 1 and return them in any order. The graph is given as follows: graph[i] is a list of all nodes you can visit from node i (i.e., there is a directed edge from node i to node graph[i][j]). https://leetcode.com/problems/all-paths-from-source-to-target/description/ class Solution { public List<List<Integer>> allPathsSourceTarget(int[][] ...

Leetcode 1167: Minimum Cost to Connect Sticks

You have some number of sticks with positive integer lengths. These lengths are given as an array sticks, where sticks[i] is the length of the ith stick. You can connect any two sticks of lengths x and y into one stick by paying a cost of x + y. You must connect all the sticks until there is only one stick remaining. Return the minimum cost of connecting ...

Leetcode 1834: Single-Threaded CPU

You are given n​​​​​​ tasks labeled from 0 to n - 1 represented by a 2D integer array tasks, where tasks[i] = [enqueueTimei, processingTimei] means that the i​​​​​​th​​​​ task will be available to process at enqueueTimei and will take processingTimeito finish processing. You have a single-threaded CPU that can process at most one task at a time and will act in the following way: If the CPU is idle ...

Find and Replace Pattern

Title: Find and Replace Pattern Source: leetcode.com You have a list of words and a pattern, and you want to know which words in words matches the pattern. A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get ...

Linked List Components

Title: Linked List Components Source: leetcode.com We are given head, the head node of a linked list containing unique integer values. We are also given the list G, a subset of the values in the linked list. Return the number of connected components in G, where two values are connected if they appear consecutively in ...