可整除子串的数量

/*
 * Leetcode 2950: Number of Divisible Substrings
 * Given a string s, return the number of substrings of s that are divisible by k.
 * 
 * Approach using Java Streams:
 * 1. Generate all substrings of s using IntStream.
 * 2. Filter the substrings that are divisible by k.
 * 3. Count the number of valid substrings.
 */
import java.util.stream.IntStream;

public class Solution {
    public long countDivisibleSubstrings(String s, int k) {
        return IntStream.range(0, s.length())
                .boxed()
                .flatMap(i -> IntStream.range(i + 1, s.length() + 1)
                        .mapToObj(j -> s.substring(i, j)))
                .filter(subStr -> !subStr.isEmpty() && Integer.parseInt(subStr) % k == 0)
                .count();
    }
}