README_EN.md

219. Contains Duplicate II

中文文档

Description

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

Solutions

Python3

class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        helper = {}
        for i, v in enumerate(nums):
            if v in helper and i - helper[v] <= k:
                return True
            helper[v] = i
        return False

Java

class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        Map<Integer, Integer> helper = new HashMap<>();
        for (int i = 0, n = nums.length; i < n; ++i) {
            if (helper.containsKey(nums[i])) {
                int j = helper.get(nums[i]);
                if (i - j <= k) {
                    return true;
                }
            }
            helper.put(nums[i], i);
        }
        return false;
    }
}

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