Backtracking Algorithm Practice: Generating Valid Parentheses

labuladongOriginalAbout 2017 words

This article will resolve

LeetCode	Difficulty
22. Generate Parentheses	🟠

Prerequisites

Before reading this article, you need to learn:

Bracket problems can be divided into two types. One is checking if brackets are valid, which I have covered before. The other is generating valid parentheses. To check if brackets are valid, we usually use a stack. To generate all valid combinations, we often use backtracking to try all possible ways.

Now, let's look at LeetCode Problem 22: Generate Parentheses. The task is:

22. Generate Parentheses | LeetCode | 🟠

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

Example 1:

Input: n = 3
Output: ["((()))","(()())","(())()","()(())","()()()"]

Example 2:

Input: n = 1
Output: ["()"]

Constraints:

1 <= n <= 8

The problem is from LeetCode 22. Generate Parentheses.

The function signature is:

java

List<String> generateParenthesis(int n);

cpp

vector<string> generateParenthesis(int n);

python

def generateParenthesis(n: int) -> List[str]:

func generateParenthesis(n int) []string

javascript

var generateParenthesis = function(n) {};

For bracket problems, just remember the following key points and you will find the solution easily:

Backtracking Algorithm Practice: Generating Valid Parentheses

22. Generate Parentheses https://leetcode.com/problems/generate-parentheses

Backtracking Idea