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Leetcode
Easy
Arrays
Strings
Counting Words With A Given Prefix

Count how many words in a list start with a given prefix.

Acceptance 0%
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Problem Statement

Problem

You are given a list of words and a prefix string. Return how many words begin with that prefix.

A word is considered a match if the prefix appears at the start of the word exactly, character by character.

Goal

Write a function that counts the matching words efficiently and returns the total number of matches.

Input Format

  • A list of strings words
  • A string pref representing the prefix to match

Output Format

  • Return a single integer: the number of words in words that start with pref

Constraints

  • 1 <= words.length
  • Each word and the prefix contain lowercase English letters
  • The prefix may be empty in generalized settings, but for interview practice assume it is non-empty unless stated otherwise
Examples
Sample cases returned by the problem API.

Example 1

Input

words = ["pay", "attention", "practice", "attend"], pref = "at"

Output

2

Explanation

"attention" and "attend" start with "at".

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