标签：contains ase put whether and dice span table ret
Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most 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
improved hash table solution: keep a sliding window of k elements using Hash Table.
time = O(n), space = O( min(n, k) )
class Solution { public boolean containsNearbyDuplicate(int[] nums, int k) { Set<Integer> set = new HashSet<>(); for(int i = 0; i < nums.length; i++) { if(set.contains(nums[i])) { return true; } set.add(nums[i]); if(set.size() > k) { set.remove(nums[i - k]); } } return false; } }
naive hash table solution:
time = O(n), space = O(n)
class Solution { public boolean containsNearbyDuplicate(int[] nums, int k) { Map<Integer, List<Integer>> map = new HashMap<>(); for(int i = 0; i < nums.length; i++) { map.putIfAbsent(nums[i], new ArrayList<>()); map.get(nums[i]).add(i); } for(Map.Entry<Integer, List<Integer>> entry : map.entrySet()) { List<Integer> idx = entry.getValue(); for(int i = 0; i < idx.size() - 1; i++) { if(idx.get(i + 1) - idx.get(i) <= k) { return true; } } } return false; } }
219. Contains Duplicate II - Easy
标签：contains ase put whether and dice span table ret
原文地址：https://www.cnblogs.com/fatttcat/p/11331992.html
