等差数列划分

/*
 * Problem Statement:
 * An arithmetic sequence is defined as a sequence of at least three elements where the difference between consecutive elements is constant.
 * Given an integer array nums, return the number of all the arithmetic subarrays of nums.
 * A subarray is a contiguous subsequence of the array.
 * 
 * Approach using Java Streams:
 * 1. Initialize a variable to store the count of arithmetic subarrays.
 * 2. Use IntStream to iterate through the array and find all subarrays with at least 3 elements.
 * 3. For each subarray, check if it forms an arithmetic sequence by comparing the difference between consecutive elements.
 * 4. Count all valid arithmetic subarrays.
 */
 
import java.util.stream.IntStream;
 
public class ArithmeticSubarraysStream {
    public int numberOfArithmeticSlices(int[] nums) {
        int[] count = {0};
        IntStream.range(0, nums.length - 2).forEach(i -> {
            int diff = nums[i + 1] - nums[i];
            IntStream.range(i + 2, nums.length).takeWhile(j -> nums[j] - nums[j - 1] == diff).forEach(j -> count[0]++);
        });
        return count[0];
    }
}