package top100liked

import (
	"fmt"
	"testing"
)

// https://leetcode.cn/problems/generate-parentheses/description/?envType=study-plan-v2&envId=top-100-liked

func generateParenthesis(n int) []string {
	res := []string{}
	r := []byte{}
	num_l := 0
	num_r := 0

	var helper func()
	helper = func() {
		if num_l < n {
			r = append(r, '(')
			num_l++
			helper()
			num_l--
			r = r[:len(r)-1]
		}
		if num_l > num_r {
			r = append(r, ')')
			num_r++
			helper()
			num_r--
			r = r[:len(r)-1]
		}
		if num_l == n && num_r == n {
			res = append(res, string(r))
		}
	}

	helper()

	return res
}

func Test(t *testing.T) {
	fmt.Printf("%+v\n", generateParenthesis(3))
}

func Test2(t *testing.T) {
	fmt.Printf("%+v\n", generateParenthesis(1))
}