What is the easiest way to find words containing a character in an array?

Loop through each word and check each character for a match with the target character. Collect the indices when matches are found.

Can the returned indices be in any order?

Yes, the order of indices does not matter as long as every word containing the character is included.

What if no words contain the character?

Return an empty array since no indices correspond to matches.

How does this relate to the array plus string pattern?

The pattern involves iterating over an array of strings and performing character-level checks, exactly as required here.

What are the constraints for this problem?

Array length is 1 to 50, each word length 1 to 50, all lowercase letters, and the target character is lowercase.

#2942

Easy

auto_awesome数组·string

LeetCode 题解工作台

查找包含给定字符的单词

给你一个下标从 0 开始的字符串数组 words 和一个字符 x 。请你返回一个下标数组，表示下标在数组中对应的单词包含字符 x 。注意，返回的数组可以是任意顺序。示例 1：输入： words = ["leet","code"], x = "e" 输出： [0,1] 解释： "e"…

数组字符串

题目描述

给你一个下标从 0 开始的字符串数组 words 和一个字符 x 。

请你返回一个 下标数组 ，表示下标在数组中对应的单词包含字符 x 。

注意，返回的数组可以是任意顺序。

示例 1：

输入：words = ["leet","code"], x = "e"
输出：[0,1]
解释："e" 在两个单词中都出现了："leet" 和 "code" 。所以我们返回下标 0 和 1 。

示例 2：

输入：words = ["abc","bcd","aaaa","cbc"], x = "a"
输出：[0,2]
解释："a" 在 "abc" 和 "aaaa" 中出现了，所以我们返回下标 0 和 2 。

示例 3：

输入：words = ["abc","bcd","aaaa","cbc"], x = "z"
输出：[]
解释："z" 没有在任何单词中出现。所以我们返回空数组。

提示：

1 <= words.length <= 50
1 <= words[i].length <= 50
x 是一个小写英文字母。
words[i] 只包含小写英文字母。

lightbulb

解题思路

方法一：遍历

我们直接遍历字符串数组 $words$ 中的每一个字符串 $words[i]$ ，如果 $x$ 在 $words[i]$ 中出现，就将 $i$ 加入答案数组中。

遍历结束后，返回答案数组即可。

时间复杂度 $O(L)$ ，其中 $L$ 为字符串数组 $words$ 中所有字符串的长度和。忽略答案数组的空间消耗，空间复杂度 $O(1)$ 。

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class Solution:
    def findWordsContaining(self, words: List[str], x: str) -> List[int]:
        return [i for i, w in enumerate(words) if x in w]

speed

复杂度分析

指标	值
时间	O(n * m)
空间	O(1)

psychology

面试官常问的追问

外企场景

question_mark
Does the candidate correctly iterate through both the array and characters within each word?
question_mark
Is the candidate returning the indices rather than the words themselves?
question_mark
Does the solution handle cases where no words contain the target character?

warning

常见陷阱

外企场景

error
Returning words instead of indices.
error
Assuming the array or words are sorted and returning incorrect order.
error
Missing cases where no words contain the character, resulting in null or incorrect output.

swap_horiz

进阶变体

外企场景

arrow_right_alt
Return words containing the character instead of their indices.
arrow_right_alt
Count how many times the character occurs in each word and return those counts.
arrow_right_alt
Find indices of words containing multiple specified characters simultaneously.

help

常见问题

外企场景

继续练习

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