LeetCode 219: Contains Duplicate II Solution
Master LeetCode problem 219 (Contains Duplicate II), a easy challenge, with our optimized solutions in Java, C++, and Python. Explore detailed explanations, test your code in our interactive editor, and prepare for coding interviews.
219. Contains Duplicate II
Problem Explanation
Explanation
To solve this problem, we can iterate through the array and keep track of the indices of each number we encounter using a HashMap. For each number, if it already exists in the HashMap, we check if the absolute difference of the current index and the previous index of that number is less than or equal to k. If it is, we return true. If we finish iterating through the array without finding any such pair, we return false.
- Time complexity: O(n) where n is the number of elements in the array.
- Space complexity: O(min(n, k)) where n is the number of elements in the array and k is the value of k.
Solution Code
import java.util.HashMap;
class Solution {
public boolean containsNearbyDuplicate(int[] nums, int k) {
HashMap<Integer, Integer> map = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
if (map.containsKey(nums[i]) && i - map.get(nums[i]) <= k) {
return true;
}
map.put(nums[i], i);
}
return false;
}
}Try It Yourself
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