LeetCode-in-Java
3392. Count Subarrays of Length Three With a Condition
Easy
Given an integer array nums, return the number of subarrays of length 3 such that the sum of the first and third numbers equals exactly half of the second number.
A subarray is a contiguous non-empty sequence of elements within an array.
Example 1:
Input: nums = [1,2,1,4,1]
Output: 1
Explanation:
Only the subarray [1,4,1] contains exactly 3 elements where the sum of the first and third numbers equals half the middle number.
Example 2:
Input: nums = [1,1,1]
Output: 0
Explanation:
[1,1,1] is the only subarray of length 3. However, its first and third numbers do not add to half the middle number.
Constraints:
3 <= nums.length <= 100-100 <= nums[i] <= 100
Solution
public class Solution {
public int countSubarrays(int[] nums) {
int window = 3;
int cnt = 0;
for (int i = 0; i <= nums.length - window; i++) {
float first = nums[i];
float second = nums[i + 1];
float third = nums[i + 2];
if (second / 2 == first + third) {
cnt++;
}
}
return cnt;
}
}