140. 单词拆分 II

Java错误代码：不该回溯数组的，回溯数组是以固定顺序来的，应该回溯字符串！

class Solution {
    StringBuilder sb;
    List<String> list;
    List<String> tmp;

    private String getString() {
        StringBuilder str = new StringBuilder();
        for (int i = 0; i < tmp.size(); i++) {
            str.append(tmp.get(i));
        }
        return str.toString();
    }

    private String getString1() {
        StringBuilder str = new StringBuilder();
        for (int i = 0; i < tmp.size() - 1; i++) {
            str.append(tmp.get(i));
            str.append(" ");
        }
        str.append(tmp.get(tmp.size() - 1));
        return str.toString();
    }

    private void dfs(int pos, String str, String s, List<String> wordDict) {
        if (s.equals(str)) {
            list.add(getString1());
        }
        for (int i = pos; i < wordDict.size(); ++i) {
            tmp.add(wordDict.get(i));  // 艹 写了半天发现是以任意顺序
            String s1 = getString();
            if (s1.length() <= s.length() && s.startsWith(s1)) {
                dfs(i + 1, s1, s, wordDict);
            }
            tmp.remove(tmp.size() - 1);
        }
    }

    public List<String> wordBreak(String s, List<String> wordDict) {
        sb = new StringBuilder();
        list = new ArrayList<>();
        tmp = new ArrayList<>();

        dfs(0, "", s, wordDict);
        return list;
    }
}