Skip to content

3471. Find the Largest Almost Missing Integer

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

An integer x is almost missing from nums if x appears in exactly one subarray of size k within nums.

Return the largest almost missing integer from nums. If no such integer exists, return -1.

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

Example 1

Input: nums = [3,9,2,1,7], k = 3
Output: 7
Explanation:
- 1 appears in 2 subarrays of size 3: [9, 2, 1] and [2, 1, 7].
- 2 appears in 3 subarrays of size 3: [3, 9, 2], [9, 2, 1], [2, 1, 7].
- 3 appears in 1 subarray of size 3: [3, 9, 2].
- 7 appears in 1 subarray of size 3: [2, 1, 7].
- 9 appears in 2 subarrays of size 3: [3, 9, 2], and [9, 2, 1].
We return 7 since it is the largest integer that appears in exactly one subarray of size k.

Example 2

Input: nums = [3,9,7,2,1,7], k = 4
Output: 3
Explanation:
- 1 appears in 2 subarrays of size 4: [9, 7, 2, 1], [7, 2, 1, 7].
- 2 appears in 3 subarrays of size 4: [3, 9, 7, 2], [9, 7, 2, 1], [7, 2, 1, 7].
- 3 appears in 1 subarray of size 4: [3, 9, 7, 2].
- 7 appears in 3 subarrays of size 4: [3, 9, 7, 2], [9, 7, 2, 1], [7, 2, 1, 7].
- 9 appears in 2 subarrays of size 4: [3, 9, 7, 2], [9, 7, 2, 1].
We return 3 since it is the largest and only integer that appears in exactly one subarray of size k.

Example 3

Input: nums = [0,0], k = 1
Output: -1
Explanation:
There is no integer that appears in only one subarray of size 1.

Constraints

  • 1 <= nums.length <= 50
  • 0 <= nums[i] <= 50
  • 1 <= k <= nums.length