标签：class blog code java com get
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:
"((()))", "(()())", "(())()", "()(())", "()()()"
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public class Solution { /**In order to generate valid parenthesis, the number of * "(" should not smaller than the number of ")". So, we use a List<Integer> * to save the number of "(". So the number of ")" can be calculated. * @param n --Integer, number of parentheses * @return List of valid parentheses strings * @author Averill Zheng * @version 2014-06-04 * @since JDK 1.7 */ public
List<String> generateParenthesis(int
n) { List<String> validParen = new
ArrayList<String>(); List<Integer> numberOfLeftParen = new
ArrayList<Integer>(); if(n > 0){ validParen.add("("); numberOfLeftParen.add(1); for(int
i = 2; i <= 2*n; ++i){ List<String> tempValidParen = new
ArrayList<String>(); List<Integer> num = new
ArrayList<Integer>(); int
length = validParen.size(); for(int
j = 0; j < length; ++j){ //the length of string in list now is i - 1 int
leftParen = numberOfLeftParen.get(j); // it implies that number of ")" is i - 1 - leftParen String s = validParen.get(j); if(leftParen == n){ tempValidParen.add(s + ")"); num.add(leftParen); } else
if(leftParen <= (i - 1
- leftParen)){ tempValidParen.add(s + "("); num.add(leftParen + 1); } else{ tempValidParen.add(s + "("); num.add(leftParen + 1); tempValidParen.add(s + ")"); num.add(leftParen); } } validParen = tempValidParen; numberOfLeftParen = num; } } return
validParen; }} |
leetcode--Generate Parentheses,布布扣,bubuko.com
leetcode--Generate Parentheses
标签：class blog code java com get
原文地址：http://www.cnblogs.com/averillzheng/p/3772537.html
