检索以数组中的字符串为前缀的字符串

Question

Write a Java code of the method that takes an array of strings and a String (S(. The method should return an integer that is the number of strings that starts with S.

For example if: array_words = { "All", "Arab", "size", "Almond", "Allowed", "here"} and S= "All", then the method should return 2

what is the idea of searching here ?

Answer 1

The best, fastest and cheapest solution, for a larger input though, is to store all words of the array into a DWAG .

That would bring the memory requirements to almost optimal for storing all words and would give a search time complexity of O(m) (m being the size of S).

A slightly less memory optimal structure would be a trie .

Some people ask homework questions sometimes on SOF, and sometimes they get answers a little out of scope.

Answer 2

Loop through the array and use the startsWith method.

I know you can take it up from here.

Answer 3

Iterate over the array and check if each element in the array starts with string S. If it does, increment the count variable.

Return the count variable after iterating over the array.

public class stack {
    public static void main(String[] args) {

        String[] arr = { "All", "Arab", "size", "Almond", "Allowed", "here"};
        String S = "All";
        System.out.println(numberOfOccurrences(S, arr));

    }

    public static int numberOfOccurrences(String S, String[] array_words) {

        int count = 0;
        for (String stringElement : array_words) {
            if (stringElement.startsWith(S)) {
                count++;
            }
        }

        return count;
    }
}