More:【目錄】LeetCode Java實現html
https://leetcode.com/problems/contains-duplicate-ii/java
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 absolutedifference between i and j is at most k.post
Example 1:ui
Input: nums = [1,2,3,1], k = 3 Output: true
Example 2:spa
Input: nums = [1,0,1,1], k = 1 Output: true
Example 3:code
Input: nums = [1,2,3,1,2,3], k = 2 Output: false
hashSethtm
public boolean containsNearbyDuplicate(int[] nums, int k) { if(nums == null) return false; HashSet<Integer> set = new HashSet<>(); for(int i=0; i<nums.length;i++){ if(i>k) set.remove(nums[i-k-1]); if(!set.add(nums[i])) return true; } return false; }
Time complexity : O(n)
blog
Space complexity : O(k)ip
1. set.add(e) returns false if the set already contains the specified element. ci
More:【目錄】LeetCode Java實現