Leetcode22: bracket generation

subject

• 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

solution

  private static List<String> generate(int n) {
        List<String> dataList=new ArrayList<>();
        if (n==0)return dataList;
        dfs("",n,n,dataList);
        return dataList;
    }

• DFS Do subtraction

  private static void dfs(String current, int left, int right, List<String> dataList) {
        //  The end of recursion is added to list in 
        if (left==0&&right==0){
            dataList.add(current);
            return;
        }
        if (left>right){
            return;
        }

        if (left>0){
            dfs(current+"(",left-1,right,dataList);
        }
        if (right>0){
            dfs(current+")",left,right-1,dataList);
        }

    }

• DFS Addition method

    private static void dfsIncrease(String current, int left, int right,int length, List<String> dataList) {
        //  The end of recursion is added to list in 
        if (left==length&&right==length){
            dataList.add(current);
            return;
        }
        if (left<right){
            return;
        }

        if (left<length){
            dfsIncrease(current+"(",left+1,right,length,dataList);
        }
        if (right<length){
            dfsIncrease(current+")",left,right+1,length,dataList);
        }

    }

• Reference resources ： https://leetcode-cn.com/problems/generate-parentheses/solution/hui-su-suan-fa-by-liweiwei1419/