Contains Duplicate II

Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <= k.

Example 1:

Input: nums = [1,2,3,1], k = 3
Output: true

Example 2:

Input: nums = [1,0,1,1], k = 1
Output: true

Example 3:

Input: nums = [1,2,3,1,2,3], k = 2
Output: false

Constraints:

• 1 <= nums.length <= 105
• -109 <= nums[i] <= 109
• 0 <= k <= 105

SOLUTION:

class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        valIndex = {}
        for i, num in enumerate(nums):
            if num in valIndex:
                curr = valIndex[num][-1]
                if i - curr <= k:
                    return True
                valIndex[num].append(i)
            else:
                valIndex[num] = [i]
        return False