Practice/Datadog/Leetcode 819. Most Common Word

Leetcode 819. Most Common Word

CodingMust

Problem

You are given a text paragraph containing words separated by spaces and various punctuation marks. You are also given a list of banned words that should be ignored during analysis.

Your task is to find and return the most frequently occurring word in the paragraph that is not in the banned list. The comparison should be case-insensitive, and all punctuation should be removed when identifying words.

Requirements

1. Convert the entire paragraph to lowercase for case-insensitive comparison
2. Remove all punctuation marks and treat them as word separators
3. Count the frequency of each word, excluding any words that appear in the banned list
4. Return the word with the highest frequency that is not banned
5. If there are multiple words with the same highest frequency, return any one of them

Constraints

• 1 ≤ paragraph.length ≤ 1000
• 0 ≤ banned.length ≤ 100
• 1 ≤ banned[i].length ≤ 10
• The paragraph contains only lowercase and uppercase English letters, spaces, and punctuation marks: !?',;.
• There will be at least one non-banned word in the paragraph
• All words in the banned list are lowercase

Examples

Example 1:

Input: paragraph = "Apple! Apple? Banana.", banned = [] Output: "apple" Explanation: After normalization, "apple" appears 2 times and "banana" appears 1 time. Since no words are banned, "apple" is the most frequent word.

Example 2:

Input: paragraph = "a, a, a, a, b,b,b,c, c", banned = ["a"] Output: "b" Explanation: After normalization, "a" appears 4 times, "b" appears 3 times, and "c" appears 2 times. Since "a" is banned, "b" becomes the most frequent valid word.

Example 3:

Input: paragraph = "Hello world! Hello everyone.", banned = ["world"] Output: "hello" Explanation: "hello" appears 2 times, "world" appears 1 time (but is banned), and "everyone" appears 1 time. "hello" is the most frequent non-banned word.