LeetCode：palindrome-partitioning

題目描述

 

Given a string s, partition s such that every substring of the partition is a palindrome.

Return all possible palindrome partitioning of s.

For example, given s ="aab",
Return

  [
    ["aa","b"],
    ["a","a","b"]
  ]

import java.util.ArrayList;

public class Solution {
	public ArrayList<ArrayList<String>> partition(String s) {
		ArrayList<ArrayList<String>> lists = new ArrayList<ArrayList<String>>();
		if (s.length() == 0) {
			return lists;
		}
		ArrayList<String> array = new ArrayList<String>();
		dfs(s, array, lists);
		return lists;

	}

	// 深搜
	private void dfs(String s, ArrayList<String> array, ArrayList<ArrayList<String>> lists) {
		// TODO Auto-generated method stub
		if (null == s || s.length() == 0) {
			lists.add(new ArrayList(array));
			return;
		}
		for (int i = 1; i <= s.length(); i++) {
			String substr = s.substring(0, i);
			if (is_palindrome(substr)) {
				array.add(substr);
				dfs(s.substring(i), array, lists);
				array.remove(array.size() - 1);
			}
		}

	}

	// 判斷是否是迴文
	private boolean is_palindrome(String substr) {
		// TODO Auto-generated method stub
		if (substr.length() < 2) {
			return true;
		}
		int left = 0;
		int right = substr.length() - 1;
		while (left < right) {
			if (substr.charAt(left) != substr.charAt(right)) {
				return false;
			}
			left++;
			right--;
		}
		return true;
	}

}