3213. Count Subarrays Where Max Element Appears At Least K Times¶

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3213. Count Subarrays Where Max Element Appears at Least K Times

Medium

You are given an integer array nums and a positive integer k.

Return the number of subarrays where the maximum element of nums appears at least k times in that subarray.

A subarray is a contiguous sequence of elements within an array.

Example 1:

Input: nums = [1,3,2,3,3], k = 2
Output: 6
Explanation: The subarrays that contain the element 3 at least 2 times are: [1,3,2,3], [1,3,2,3,3], [3,2,3], [3,2,3,3], [2,3,3] and [3,3].

Example 2:

Input: nums = [1,4,2,1], k = 3
Output: 0
Explanation: No subarray contains the element 4 at least 3 times.

Constraints:

• 1 <= nums.length <= 105
• 1 <= nums[i] <= 106
• 1 <= k <= 105

Solution¶

class Solution {
    public long countSubarrays(int[] nums, int k) {
        int mx = Arrays.stream(nums).max().getAsInt();
        long ans = 0;
        int l = 0,r = 0,n = nums.length;
        while (r < n) {
            k -= nums[r] == mx ? 1 : 0;
            r++;
            while (k == 0) {
                k += nums[l] == mx ? 1 : 0;
                l++;
            }
            ans += l;
        }
        return ans;
    }
}

Complexity Analysis¶

• Time Complexity: O(?)
• Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here