Say you have an array for which the ith element is the price of a given stock on day i.
If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.
Example 1: Input: [7, 1, 5, 3, 6, 4] Output: 5
| class Pet(object): | |
| def __init__(self, name, species): | |
| self.name = name | |
| self.species = species | |
| def getName(self): | |
| return self.name | |
| def getSpecies(self): |
Two of the most commonly used data structures in web development are stacks and queues. The history of pages visited in a web browser and the undo operation in a text editor are examples of operations made possible using stacks. The handling of events in web browsers often uses a queue data structure.
A stack is a data structure that stores elements in a LIFO (Last In First Out) order. It's like a stack of plates in your kitchen. When a plate is added, it is pushed towards the bottom of a stack. The last plate that you stack becomes the one on the top of the stack and it is the first one that you get to use.
A stack has two basic functions:
[Source][1]
In earlier chapters, variables have been explained as locations in the computer's memory which can be accessed by their identifier (their name). This way, the program does not need to care about the physical address of the data in memory; it simply uses the identifier whenever it needs to refer to the variable.
For a C++ program, the memory of a computer is like a succession of memory cells, each one byte in size, and each with a unique address. These single-byte memory cells are ordered in a way that allows data representations larger than one byte to occupy memory cells that have consecutive addresses.
This way, each cell can be easily located in the memory by means of its unique address. For example, the memory cell with the address 1776 always follows immediately after the cell with address 1775 and precedes the one with 1777, and is exactly one thousand cells after 776 and exactly one thousand cells before 2776.
When a variable is declared, the memory needed
| ActiveRecord cheat sheet / EXAMPLES | |
| INSTALL | |
| ======= | |
| $ gem install activerecord | |
| in GEMFILE: gem ‘activerecord’ | |
| REQUIRE | |
| ======= | |
| require ‘active_record’ |
| # Define recode_sex() | |
| # Recoding variables is a common data cleaning task. Functions provide a mechanism for you to abstract away complex bits of code as well as # reuse code. This makes your code more readable and less error prone. | |
| # You can use the .apply() method to apply a function across entire rows or columns of DataFrames. However, note that each column of a DataFrame # is a pandas Series. Functions can also be applied across Series. Here, you will apply your function over the 'sex' column. | |
| def recode_sex(sex_value): | |
| # Return 1 if sex_value is 'Male' | |
| if sex_value == 'Male': | |
| return 1 | |
