2444. Count Subarrays With Fixed Bounds

Problem

You are given an integer array nums and two integers minK and maxK.

A fixed-bound subarray of nums is a subarray that satisfies the following conditions:

• The minimum value in the subarray is equal to minK.
• The maximum value in the subarray is equal to maxK.

Return the number of fixed-bound subarrays.

A subarray is a contiguous part of an array.

Example 1:

Input: nums = [1,3,5,2,7,5], minK = 1, maxK = 5
Output: 2
Explanation: The fixed-bound subarrays are [1,3,5] and [1,3,5,2].

Example 2:

Input: nums = [1,1,1,1], minK = 1, maxK = 1
Output: 10
Explanation: Every subarray of nums is a fixed-bound subarray. There are 10 possible subarrays.

Constraints:

• 2 <= nums.length <= 10^5

• 1 <= nums[i], minK, maxK <= 10^6

Solution (Java)

class Solution {
    public long countSubarrays(int[] A, int minK, int maxK) {
        long res = 0, jbad = -1, jmin = -1, jmax = -1, n = A.length;
        for (int i = 0; i < n; ++i) {
            if (A[i] < minK || A[i] > maxK) jbad = i;
            if (A[i] == minK) jmin = i;
            if (A[i] == maxK) jmax = i;
            res += Math.max(0L, Math.min(jmin, jmax) - jbad);
        }
        return res;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).