［抄题］：
In English, we have a concept called root, which can be followed by some other words to form another longer word - let's call this word successor. For example, the root an, followed by other, which can form another word another.
Now, given a dictionary consisting of many roots and a sentence. You need to replace all the successor in the sentence with the root forming it. If a successor has many roots can form it, replace it with the root with the shortest length.
You need to output the sentence after the replacement.
Example 1:
Input: dict = ["cat", "bat", "rat"]
sentence = "the cattle was rattled by the battery"
Output: "the cat was rat by the bat"
[暴力解法]：
时间分析：
空间分析：
[优化后]：
时间分析：
空间分析：
［奇葩输出条件］：
［奇葩corner case］：
［思维问题］：
不知道怎么取单词前半截：.substring都忘了，实在是太弱了。
［英文数据结构或算法，为什么不用别的数据结构或算法］：
［一句话思路］：
［输入量］：空： 正常情况：特大：特小：程序里处理到的特殊情况：异常情况（不合法不合理的输入）：
［画图］：
［一刷］：
substring包左不包右，所以i需要 i <= word.length多加一位
［二刷］：
［三刷］：
［四刷］：
［五刷］：
[五分钟肉眼debug的结果]：
［总结］：
取前半截用substring，而且右边界的i不包，要包就要加<=i的等号
［复杂度］：Time complexity: O(n) Space complexity: O(n)
［算法思想：迭代/递归/分治/贪心］：
［关键模板化代码］：
［其他解法］：
［Follow Up］：
［LC给出的题目变变变］：
[代码风格] ：
[是否头一次写此类driver funcion的代码] ：
[潜台词] ：
class Solution { public String replaceWords(List<String> dict, String sentence) { //corner case if (dict == null || sentence.length() == 0) return ""; //initialization: set Set<String> set = new HashSet<String>(); //put all the words into set for (int i = 0; i < dict.size(); i++) { set.add(dict.get(i)); } //append the new result StringBuilder sb = new StringBuilder(); String[] words = sentence.split("\s+"); for (String word : words) { String prefix = ""; for (int i = 1; i <= word.length(); i++) { prefix = word.substring(0, i); if (set.contains(prefix)) break; } sb.append(" " + prefix); } //return return sb.deleteCharAt(0).toString(); } }