3685. Count Subarrays Of Length Three With A Condition¶
3685. 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¶
class Solution {
public int countSubarrays(int[] nums) {
int n = nums.length;
int count = 0, i = 0, j = 2;
while (j < n) {
if (2 * (nums[i] + nums[j]) == nums[i + 1]) count++;
i++; j++;
}
return count;
}
}
Complexity Analysis¶
- Time Complexity: O(?)
- Space Complexity: O(?)
Explanation¶
[Add detailed explanation here]