Gain insights into competitive programming, explore C++ skills with theory, code samples, practice problems, and master faster implementation for contests like ACM ICPC, Google CodeJam, and HackerCup.

Competitive programming can be a great way to build out your programming skills, get on any major company’s radar, and earn a little extra cash along the way.

In this course, you will learn to prepare for competitive programming contests like ACM ICPC, Google CodeJam, Facebook HackerCup, and many more.

Each topic is broken down with a healthy mix of theory, code samples, step-by-step solved sample problems, illustrations, useful practice problems, and tips and tricks for faster implementation.

You will need some solid C++ foundations coming into this course, but by the end it, you will be confident enough in your C++ skills to take home the win.

Competitive Programming in C++: The Keys to Success

## Library
While solving a problem, we’ll be using heap from C++ STL (`priority_queue`).

Below are some of the operations that we’ll use frequently. For complete documentation about how they work, check [here](http://www.cplusplus.com/reference/queue/priority_queue/).

> By default, in C++, `priority_queue` is a **max heap**.

```
priority_queue<int> Q; //empty heap
int x = Q.top(); // get top element
Q.pop(); // pop top element (maximum element)
Q.push(x); //add x to the heap
bool x = Q.empty(); // to check if heap is empty
int sz = Q.size(); // get size of heap
```

---

## Min heap
There are two ways to use `priority_queue` as a min-heap.

### Insert negative elements
Min heap for `[2, -3, 4, -1]` is just Max heap for `[-2, 3, -4, 1]`.

### Use three arguments constructor
`priority_queue<T>` has three argument overloaded constructor.

`priority_queue <Type, Container, Compare>`. The default values are

* Container: `vector<Type>`
* Compare: `less<Type>`

Below is the declaration for min-heap:

`priority_queue <int, vector<int>, greater<int> > Q;`

---

In the next lesson, we'll discuss a solved problem using heaps.

# Library
While solving a problem, we’ll be using heap from C++ STL (`priority_queue`).

Below are some of the operations that we’ll use frequently. For complete documentation about how they work, check [here](http://www.cplusplus.com/reference/queue/priority_queue/).

> By default, in C++, `priority_queue` is a **max heap**.

```
priority_queue<int> Q; //empty heap
int x = Q.top(); // get top element
Q.pop(); // pop top element (maximum element)
Q.push(x); //add x to the heap
bool x = Q.empty(); // to check if heap is empty
int sz = Q.size(); // get size of heap
```

---

# Min heap
There are two ways to use `priority_queue` as a min-heap.

## Insert negative elements
Min heap for `[2, -3, 4, -1]` is just Max heap for `[-2, 3, -4, 1]`.

## Use three arguments constructor
`priority_queue<T>` has three argument overloaded constructor.

`priority_queue <Type, Container, Compare>`. The default values are

* Container: `vector<Type>`
* Compare: `less<Type>`

Below is the declaration for min-heap:

`priority_queue <int, vector<int>, greater<int> > Q;`

---

In the next lesson, we'll discuss a solved problem using heaps.

In this lesson, we'll see how to use the STL priority queue as a built-in heap.


Introduction

Complexity Analysis

Number Theory

Arrays and Vectors

Sieve of Eratosthenes

Strings

Sorting

Linked List

Stack

Queue

Binary Tree

2 Pointers

Heap

Binary Search Tree

Balanced Binary Search Tree

Course Conclusion

STL

Library