Palindrome Partitioning

最新推荐文章于 2021-02-15 17:35:21 发布

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本文介绍了一种递归算法，用于将输入字符串按回文子串进行划分，并返回所有可能的回文子串组合。该算法通过深度优先搜索实现，包含回文检查辅助函数。

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

Return all possible palindrome partitioning of s.

java

public class Solution {
    /*
     * @param s: A string
     * @return: A list of lists of string
     */
    public List<List<String>> partition(String s) {
        // write your code here
        List<List<String>> result = new ArrayList<>();
        if (s == null || s.length() == 0) {
            return result;
        }
        List<String> list = new ArrayList<>();
        if (s.length() == 1) {
            list.add(s);
            result.add(list);
            return result;
        }
        dfs(s, 0, list, result);
        return result;
    }
    private void dfs(String s,
                     int startIndex, 
                     List<String> list, 
                     List<List<String>> result) {
        if (startIndex == s.length()) {
            result.add(new ArrayList<String>(list));
        }
        for (int i = startIndex; i < s.length(); i++) {
            String sub = s.substring(startIndex, i + 1);
            if (!isPalindrome(sub)) {
                continue;
            } else {
                list.add(sub);
                dfs(s, i + 1, list, result);
                list.remove(list.size() - 1);
            }
        }
    }
    private boolean isPalindrome(String s) {
        if (s == null || s.length() == 0) {
            return false;
        }
        char[] c = s.toCharArray();
        int i = 0; 
        int j = c.length - 1;
        while (i <= j) {
            if (c[i++] != c[j--]) {
                return false;
            } 
        }
        return true;
    }
}