LeetCode-in-Go

219. Contains Duplicate II

Easy

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

func containsNearbyDuplicate(nums []int, k int) bool {
	duplicates := make(map[int]int, len(nums))
	i := len(nums) - 1
	for i >= 0 {
		if idx, seen := duplicates[nums[i]]; seen {
			if idx-i <= k {
				return true
			}
		}
		duplicates[nums[i]] = i
		i--
	}
	return false
}

This site is open source. Improve this page.