{ "data": { "question": { "questionId": "2256", "questionFrontendId": "2135", "categoryTitle": "Algorithms", "boundTopicId": 1196323, "title": "Count Words Obtained After Adding a Letter", "titleSlug": "count-words-obtained-after-adding-a-letter", "content": "
You are given two 0-indexed arrays of strings startWords
and targetWords
. Each string consists of lowercase English letters only.
For each string in targetWords
, check if it is possible to choose a string from startWords
and perform a conversion operation on it to be equal to that from targetWords
.
The conversion operation is described in the following two steps:
\n\n"abc"
, the letters 'd'
, 'e'
, or 'y'
can be added to it, but not 'a'
. If 'd'
is added, the resulting string will be "abcd"
."abcd"
can be rearranged to "acbd"
, "bacd"
, "cbda"
, and so on. Note that it can also be rearranged to "abcd"
itself.Return the number of strings in targetWords
that can be obtained by performing the operations on any string of startWords
.
Note that you will only be verifying if the string in targetWords
can be obtained from a string in startWords
by performing the operations. The strings in startWords
do not actually change during this process.
\n
Example 1:
\n\n\nInput: startWords = ["ant","act","tack"], targetWords = ["tack","act","acti"]\nOutput: 2\nExplanation:\n- In order to form targetWords[0] = "tack", we use startWords[1] = "act", append 'k' to it, and rearrange "actk" to "tack".\n- There is no string in startWords that can be used to obtain targetWords[1] = "act".\n Note that "act" does exist in startWords, but we must append one letter to the string before rearranging it.\n- In order to form targetWords[2] = "acti", we use startWords[1] = "act", append 'i' to it, and rearrange "acti" to "acti" itself.\n\n\n
Example 2:
\n\n\nInput: startWords = ["ab","a"], targetWords = ["abc","abcd"]\nOutput: 1\nExplanation:\n- In order to form targetWords[0] = "abc", we use startWords[0] = "ab", add 'c' to it, and rearrange it to "abc".\n- There is no string in startWords that can be used to obtain targetWords[1] = "abcd".\n\n\n
\n
Constraints:
\n\n1 <= startWords.length, targetWords.length <= 5 * 104
1 <= startWords[i].length, targetWords[j].length <= 26
startWords
and targetWords
consists of lowercase English letters only.startWords
or targetWords
.给你两个下标从 0 开始的字符串数组 startWords
和 targetWords
。每个字符串都仅由 小写英文字母 组成。
对于 targetWords
中的每个字符串,检查是否能够从 startWords
中选出一个字符串,执行一次 转换操作 ,得到的结果与当前 targetWords
字符串相等。
转换操作 如下面两步所述:
\n\n\"abc\"
,那么字母 'd'
、'e'
或 'y'
都可以加到该字符串末尾,但 'a'
就不行。如果追加的是 'd'
,那么结果字符串为 \"abcd\"
。\"abcd\"
可以重排为 \"acbd\"
、\"bacd\"
、\"cbda\"
,以此类推。注意,它也可以重排为 \"abcd\"
自身。找出 targetWords
中有多少字符串能够由 startWords
中的 任一 字符串执行上述转换操作获得。返回 targetWords
中这类 字符串的数目 。
注意:你仅能验证 targetWords
中的字符串是否可以由 startWords
中的某个字符串经执行操作获得。startWords
中的字符串在这一过程中 不 发生实际变更。
\n\n
示例 1:
\n\n\n输入:startWords = [\"ant\",\"act\",\"tack\"], targetWords = [\"tack\",\"act\",\"acti\"]\n输出:2\n解释:\n- 为了形成 targetWords[0] = \"tack\" ,可以选用 startWords[1] = \"act\" ,追加字母 'k' ,并重排 \"actk\" 为 \"tack\" 。\n- startWords 中不存在可以用于获得 targetWords[1] = \"act\" 的字符串。\n 注意 \"act\" 确实存在于 startWords ,但是 必须 在重排前给这个字符串追加一个字母。\n- 为了形成 targetWords[2] = \"acti\" ,可以选用 startWords[1] = \"act\" ,追加字母 'i' ,并重排 \"acti\" 为 \"acti\" 自身。\n\n\n
示例 2:
\n\n\n输入:startWords = [\"ab\",\"a\"], targetWords = [\"abc\",\"abcd\"]\n输出:1\n解释:\n- 为了形成 targetWords[0] = \"abc\" ,可以选用 startWords[0] = \"ab\" ,追加字母 'c' ,并重排为 \"abc\" 。\n- startWords 中不存在可以用于获得 targetWords[1] = \"abcd\" 的字符串。\n\n\n
\n\n
提示:
\n\n1 <= startWords.length, targetWords.length <= 5 * 104
1 <= startWords[i].length, targetWords[j].length <= 26
startWords
和 targetWords
中的每个字符串都仅由小写英文字母组成startWords
或 targetWords
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