2185. Counting Words With a Given Prefix
- You are given an array of strings
wordsand a stringpref. - Return the number of strings in
wordsthat containprefas a prefix. - A prefix of a string
sis any leading contiguous substring ofs.
Example 1
Input: words = ["pay","attention","practice","attend"], pref = "at"
Output: 2
Explanation: The 2 strings that contain "at" as a prefix are: "attention" and "attend".
Example 2
Input: words = ["leetcode","win","loops","success"], pref = "code"
Output: 0
Explanation: There are no strings that contain "code" as a prefix.
Method 1
【O(n * m) time | O(1) space】
package Leetcode.String;
/**
* @author zhengxingxing
* @date 2025/01/09
*/
public class CountingWordsWithAGivenPrefix {
public static int prefixCount(String[] words, String pref) {
int count = 0;
for (String word : words) {
if (word.startsWith(pref)) {
count++;
}
}
return count;
}
public static void main(String[] args) {
// Test case 1
String[] words1 = {"pay", "attention", "practice", "attend"};
String pref1 = "at";
System.out.println("Test case 1 result: " + prefixCount(words1, pref1)); // Expected output: 2
// Test case 2
String[] words2 = {"leetcode", "win", "loops", "success"};
String pref2 = "code";
System.out.println("Test case 2 result: " + prefixCount(words2, pref2)); // Expected output: 0
// Additional test case
String[] words3 = {"apple", "app", "apartment", "ape", "banana"};
String pref3 = "ap";
System.out.println("Test case 3 result: " + prefixCount(words3, pref3)); // Expected output: 4
}
}
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