131、分割回文串

基本思想：

回溯演算法

具體實現：

程式碼：

class Solution {
    List<List<String>> lists = new ArrayList<>();
    Deque<String> deque = new LinkedList<>();
    public List<List<String>> partition(String s) {
        backTracking(s, 0);
        return lists;
    }
    
 
private void backTracking(String s, int startIndex){
        //startIndex就是分割處
        if(startIndex >= s.length()){
            lists.add(new ArrayList(deque));
            return;
        }
        for (int i = startIndex; i < s.length(); i++){
            //判斷[startIndex,i]是否迴文
            if (isPalindrome(s, startIndex, i)){
                String str 
 
= s.substring(startIndex, i+1);
                deque.addLast(str);
            }
            else{
                continue;
            }

            backTracking(s, i + 1);//尋找i+1為起始位置的子串
            deque.removeLast();
        }
    }
    private boolean isPalindrome(String s, int startIndex, int
 
 end){
        for (int i = startIndex,j = end; i < j; i++, j--){
            if (s.charAt(i) != s.charAt(j)){
                return false;
            }
        }
        return true;
    }
}