leetcode
International Morse Code defines a standard encoding where each letter is mapped to a series of dots and dashes, as follows: "a" maps to ".-", "b" maps to "-...", "c" maps to "-.-.", and so on. For
leetcode
S and T are strings composed of lowercase letters. In S, no letter occurs more than once. S was sorted in some custom order previously. We want to permute the characters of T so that they match the order that S was sorted. More specifically, if x occurs before y
leetcode
Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase. Example 1: Input: "Hello" Output: "hello" Example 2: Input: "here" Output: "here" Example 3: Input: "LOVELY" Output: "lovely" Solution in Python class
leetcode
We define the usage of capitals in a word to be right when one of the following cases holds: * All letters in this word are capitals, like "USA". * All letters in this word are not capitals, like "leetcode". * Only the first letter in this word is
leetcode
You are given a string s, return the number of segments in the string. A segment is defined to be a contiguous sequence of non-space characters. Example 1: Input: s = "Hello, my name is John" Output: 5 Explanation: The five segments are ["Hello,", "my"
leetcode
Given a string s, return the first non-repeating character in it and return its index. If it does not exist, return -1. Example 1: Input: s = "leetcode" Output: 0 Example 2: Input: s = "loveleetcode" Output: 2 Example 3: Input: s = "aabb" Output: -1 Constraints:
leetcode
Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false. Each letter in the magazine string can only be used once in your
leetcode
Given a string s, reverse only all the vowels in the string and return it. The vowels are 'a', 'e', 'i', 'o', and 'u', and they can appear in both cases. Example 1: Input: s = "hello" Output: "
leetcode
Write a function that reverses a string. The input string is given as an array of characters s. Example 1: Input: s = ["h","e","l","l","o"] Output: ["o","l","l","e"
leetcode
Given an array of strings strs, group the anagrams together. You can return the answer in any order. An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. Example 1: Input: strs = ["eat&
leetcode
Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string. Note: You must not use any built-in BigInteger library or convert the inputs to integer directly. Example 1: Input: num1 = "2", num2 = "3" Output:
leetcode
Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Clarification: What should we return when needle is an empty string? This is a great question to ask during an interview. For the purpose of this problem, we