Bracket generation ---2022/02/25

Title Description

Numbers n Represents the logarithm of the generated bracket , Please design a function , Used to be able to generate all possible and Effective Bracket combination .
Title source

Their thinking

First of all, I want to add some knowledge about depth first search and breadth first search .
Depth first search is equivalent to the prior traversal of the tree （ Starting from the root node , The order traverses the left subtree , Then traverse the right subtree first ）, Usually, the data storage concept of stack is used for calculation ; Breadth first search is equivalent to traversing the tree hierarchy , Usually, the data storage concept of queue is used for calculation .

Code implementation

class Solution {
    
    List<String> res=new ArrayList<>();
    public List<String> generateParenthesis(int n) {
    
        dfs(n,n,"");
        return res;
    }

    public void dfs(int left,int right,String curStr){
    
        if(left==0&&right==0)
        {
    
            res.add(curStr);
            return;
        }
        if(left>0){
    
            dfs(left-1,right,curStr+"(");
        }
        if(right>left){
    
            dfs(left,right-1,curStr+")");
        }
    }
}

Performance evaluation

The optimization direction has not been considered for the time being .