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Count Values With Equally Spaced Occurrences II - Video Solutions

Medium

LeetCode 4049 | Biweekly Contest 191 Q2 | Count Values With Equally Spaced Occurrences II | C++

CodeSprint
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Count Values With Equally Spaced Occurrences II - Video Solution

Watch 3 video solutions for Count Values With Equally Spaced Occurrences II, a medium level problem. This walkthrough by CodeSprint has 91 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.

Problem Statement

You are given an integer array nums.

An integer x is called special if:

  • x appears at least three times in nums.
  • All occurrences of x are equally spaced in nums. In other words, if all occurrences of x are at indices i1 < i2 < ... < im, then i2 - i1 = i3 - i2 = ... = im - im-1.

Return the number of distinct special integers in nums.

 

Example 1:

Input: nums = [1,8,1,5,1,5,8,5]

Output: 2

Explanation:

  • 1 is special because it occurs at equally spaced indices 0, 2, and 4.
  • 5 is special because it occurs at equally spaced indices 3, 5, and 7.
  • 8 is not special because it occurs only twice.

Therefore, the answer is 2.

Example 2:

Input: nums = [8,8,8,8]

Output: 1

Explanation:

8 is special because it occurs at equally spaced indices 0, 1, 2, and 3. Therefore, the answer is 1.

Example 3:

Input: nums = [8,6,6,8,8]

Output: 0

Explanation:

8 occurs at indices 0, 3, and 4, which are not equally spaced. 6 occurs only twice. Therefore, no integer is special.

 

Constraints:

  • 3 <= nums.length <= 105
  • 1 <= nums[i] <= 109
Read full problem with examples