LeetCode in Net

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

public class Solution {
    public bool ContainsNearbyDuplicate(int[] nums, int k) {
        var map = new Dictionary<int, int>();
        int len = nums.Length;
        for (int i = 0; i < len; i++) {
            if (map.TryGetValue(nums[i], out int index) && Math.Abs(index - i) <= k) {
                return true;
            }
            map[nums[i]] = i;
        }
        return false;
    }
}

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