Generate Parentheses
给定一个数字n，生成符合要求的n对括号
Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
For example, given n = 3, a solution set is:
"((()))", "(()())", "(())()", "()(())", "()()()"
1 package com.rust.TestString; 2 3 import java.util.ArrayList; 4 import java.util.List; 5 6 class solution { 7 List<String> res = new ArrayList<String>(); 8 public List<String> generateParenthesis(int n) { 9 if (n == 0) { 10 res.add(""); 11 return res; 12 } 13 addBrackets("", 0, 0, n);//这个递归并没有返回的条件，跑到完为止 14 return res; 15 } 16 public void addBrackets(String str,int leftB,int rightB,int n) { 17 if (leftB == n && rightB == n) { 18 res.add(str); 19 }// 每次递归进来，根据现有情况，还会分割成不同的情况 20 if (leftB < n) { 21 addBrackets(str + "(", leftB + 1, rightB, n); 22 } 23 if (rightB < leftB) { 24 addBrackets(str + ")", leftB, rightB + 1, n); 25 } 26 } 27 } 28 public class GenerateParentheses { 29 public static void main(String args[]){ 30 solution output = new solution(); 31 List<String> out = output.generateParenthesis(3); 32 System.out.println(out.size()); 33 for (int i = 0; i < out.size(); i++) { 34 System.out.println(out.get(i)); 35 } 36 } 37 }
