{ "data": { "question": { "questionId": "1097", "questionFrontendId": "1032", "categoryTitle": "Algorithms", "boundTopicId": 3689, "title": "Stream of Characters", "titleSlug": "stream-of-characters", "content": "
Design an algorithm that accepts a stream of characters and checks if a suffix of these characters is a string of a given array of strings words
.
For example, if words = ["abc", "xyz"]
and the stream added the four characters (one by one) 'a'
, 'x'
, 'y'
, and 'z'
, your algorithm should detect that the suffix "xyz"
of the characters "axyz"
matches "xyz"
from words
.
Implement the StreamChecker
class:
StreamChecker(String[] words)
Initializes the object with the strings array words
.boolean query(char letter)
Accepts a new character from the stream and returns true
if any non-empty suffix from the stream forms a word that is in words
.\n
Example 1:
\n\n\nInput\n["StreamChecker", "query", "query", "query", "query", "query", "query", "query", "query", "query", "query", "query", "query"]\n[[["cd", "f", "kl"]], ["a"], ["b"], ["c"], ["d"], ["e"], ["f"], ["g"], ["h"], ["i"], ["j"], ["k"], ["l"]]\nOutput\n[null, false, false, false, true, false, true, false, false, false, false, false, true]\n\nExplanation\nStreamChecker streamChecker = new StreamChecker(["cd", "f", "kl"]);\nstreamChecker.query("a"); // return False\nstreamChecker.query("b"); // return False\nstreamChecker.query("c"); // return False\nstreamChecker.query("d"); // return True, because 'cd' is in the wordlist\nstreamChecker.query("e"); // return False\nstreamChecker.query("f"); // return True, because 'f' is in the wordlist\nstreamChecker.query("g"); // return False\nstreamChecker.query("h"); // return False\nstreamChecker.query("i"); // return False\nstreamChecker.query("j"); // return False\nstreamChecker.query("k"); // return False\nstreamChecker.query("l"); // return True, because 'kl' is in the wordlist\n\n\n
\n
Constraints:
\n\n1 <= words.length <= 2000
1 <= words[i].length <= 2000
words[i]
consists of lowercase English letters.letter
is a lowercase English letter.4 * 104
calls will be made to query.设计一个算法:接收一个字符流,并检查这些字符的后缀是否是字符串数组 words
中的一个字符串。
例如,words = [\"abc\", \"xyz\"]
且字符流中逐个依次加入 4 个字符 'a'
、'x'
、'y'
和 'z'
,你所设计的算法应当可以检测到 \"axyz\"
的后缀 \"xyz\"
与 words
中的字符串 \"xyz\"
匹配。
按下述要求实现 StreamChecker
类:
StreamChecker(String[] words)
:构造函数,用字符串数组 words
初始化数据结构。boolean query(char letter)
:从字符流中接收一个新字符,如果字符流中的任一非空后缀能匹配 words
中的某一字符串,返回 true
;否则,返回 false
。\n\n
示例:
\n\n\n输入:\n[\"StreamChecker\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\", \"query\"]\n[[[\"cd\", \"f\", \"kl\"]], [\"a\"], [\"b\"], [\"c\"], [\"d\"], [\"e\"], [\"f\"], [\"g\"], [\"h\"], [\"i\"], [\"j\"], [\"k\"], [\"l\"]]\n输出:\n[null, false, false, false, true, false, true, false, false, false, false, false, true]\n\n解释:\nStreamChecker streamChecker = new StreamChecker([\"cd\", \"f\", \"kl\"]);\nstreamChecker.query(\"a\"); // 返回 False\nstreamChecker.query(\"b\"); // 返回 False\nstreamChecker.query(\"c\"); // 返回n False\nstreamChecker.query(\"d\"); // 返回 True ,因为 'cd' 在 words 中\nstreamChecker.query(\"e\"); // 返回 False\nstreamChecker.query(\"f\"); // 返回 True ,因为 'f' 在 words 中\nstreamChecker.query(\"g\"); // 返回 False\nstreamChecker.query(\"h\"); // 返回 False\nstreamChecker.query(\"i\"); // 返回 False\nstreamChecker.query(\"j\"); // 返回 False\nstreamChecker.query(\"k\"); // 返回 False\nstreamChecker.query(\"l\"); // 返回 True ,因为 'kl' 在 words 中\n\n\n
\n\n
提示:
\n\n1 <= words.length <= 2000
1 <= words[i].length <= 2000
words[i]
由小写英文字母组成letter
是一个小写英文字母4 * 104
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out-of-bounds<\\/code>\\u548c
use-after-free<\\/code>\\u9519\\u8bef\\u3002<\\/p>\\r\\n\\r\\n
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