algorithms_yay

A place to keep all the algorithm exercises I've done.

helpful reminders 💯

• array.unshift(somethang) - adds to the beginning of the array
• array.push(sumthing) - adds to the end of the array
• array.shift() - removes and returns the first element
• array.pop() - removes and returns the last element
• Use slice instead of delete to delete an item from an array. Using delete replaces the item with undefined instead of removing it from the array
• array.slice(fromThisIndex, rightBeforeThisIndex) - returns a new array with values from start and end paramenters
• array.splice(index, deleteCount, addThis) - returns a new array with value at index and the # of elements deleted, and replacing it with addThis value
• Careful: "In-place" does not mean "without creating any additional variables"! Rather, it means "without creating a new copy of the input." In general, an in-place function will only create additional variables that are O(1) space
• Array.prototype.push.apply(array1, array2) - to combine two arrays. array1 now has array2 appended to it. Calling the method returns the length tho
• Number.isInteger(35) returns true if the arugment is an integer
• Array.isArray([35]) returns true if the argument is an array
• Get the max or the min of an array of numbers

var numbers = [5, 458, -215];
var maxInNumbers = Math.max.apply(Math, numbers);
var minInNumbers = Max.min.apply(Math, numbers);

• Get the max or the min of two numbers: Math.min(25,2), Math.max(25,2)

stack

• first in, last out
• one way: unshift() and shift()
• another way: push() and pop()
• push() appends an item to the end of the array
• pop() removes and returns the last item in the array

stack.add = stack.push(somethang);
stack.remove = stack.pop();

var stack = [];
stack.push(2);       // stack is now [2]
stack.push(5);       // stack is now [2, 5]
var i = stack.pop(); // stack is now [2]
alert(i);            // displays 5

queue

• first in, first out
• one way: unshift() and pop()
• another way: push() and shift()
• push() inserts the passed argument at the end of the array
• shift() removes and returns the first item

queue.add = queue.push;
queue.remove = queue.shift();

var queue = [];
queue.push(2);         // queue is now [2]
queue.push(5);         // queue is now [2, 5]
var i = queue.shift(); // queue is now [5]
alert(i);              // displays 2