Contains Duplicate
Given an integer array , return if any value appears at least twice in the array, and return if every element is distinct.
Example 1:
Reverse Linked List
Given the of a singly linked list, reverse the list, and return the reversed list.
Example 1:
Isomorphic Strings
Given two strings and , determine if they are isomorphic.
Two strings and are isomorphic if the characters in can be replaced to get .
Remove Linked List Elements
203.Remove Linked List Elements
Given the of a linked list and an integer , remove all the nodes of the linked list that has , and return the new head.
Example 1:
Happy Number
Write an algorithm to determine if a number is happy.
A happy number is a number defined by the following process:
Number of 1 Bits
Write a function that takes an unsigned integer and returns the number of ‘1’ bits it has (also known as the Hamming weight.
Note:
Excel Sheet Column Number
Given a string that represents the column title as appears in an Excel sheet, return its corresponding column number.
For example:
Majority Element
Given an array of size , return the majority element.
The majority element is the element that appears more than times. You may assume that the majority element always exists in the array.
Excel Sheet Column Title
Given an integer , return its corresponding column title as it appears in an Excel sheet.
For example: