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

# Problem statement
Given a string sequence consisting of length $N$ only of opening or closing parentheses `( ) [ ] { }`, determine if the sequence is a correct bracket sequence.

For example: If $s1$ and $s2$ are correct bracket sequences, so are the following:

* $(s1)s2$
* $(s1 s2)$
* $[(\{s1\}s2)]$

But these are not:

* $)s1s2)$
* $[s1)s2$

# Sample
**Input**: 

`[()]{}{[()()]()}`

**Output**:

`Yes`

**Constraints**:

$1<=N<=10^6$

# Brute force
Obviously, if it's a balanced sequence, every opening bracket, `( [ {`, is matched to exactly one closing bracket, `) ] }`, of the same type.


We can parse to look for every closing bracket and try to find its corresponding opening bracket in the string parsed so far.


It would be the first opening bracket to its left that didn't match up with any bracket yet. So, you keep track of matched brackets as well.

If we are able to match all the brackets, then it’s a balanced sequence, otherwise it’s not.
See the illustration below for a better understanding:



In this lesson, we'll discuss a popular stack problem.


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

Solved Problem - Balanced Parentheses Sequence

Problem statement