Difficulty:easy
More:【目录】LeetCode Java实现
Description
https://leetcode.com/problems/contains-duplicate-iii/
Given an array of integers, find out whether there are two distinct indices i and j in the array such that the absolute difference between nums[i] and nums[j] is at most tand the absolute difference between i and j is at most k.
Example 1:
Input: nums = [1,2,3,1], k = 3, t = 0 Output: true
Example 2:
Input: nums = [1,0,1,1], k = 1, t = 2 Output: true
Example 3:
Input: nums = [1,5,9,1,5,9], k = 2, t = 3 Output: false
Intuition
1. treeSet
2. bucket （future work）
Solution
TreeSet
public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
if(nums==null || k<0 || t<0)
return false;
TreeSet<Integer> tree = new TreeSet<>();
for(int i=0; i<nums.length; i++){
if(i>k)
tree.remove(nums[i-k-1]);
Integer ceiling = tree.ceiling(nums[i]);
Integer floor = tree.floor(nums[i]);
if(ceiling!=null && (long)ceiling-nums[i]<=t)
return true;
if(floor!=null && (long)nums[i]-floor<=t)
return true;
tree.add(nums[i]);
}
return false;
}
Complexity
TreeSet:
Time complexity : O(nlog(min(n,k)))
Space complexity : O(min(n,k))
What I've learned
1. treeSet.ceiling(e) && treeSet.floor(e)
2. Pay attention to overflow problems: difference of two values may smaller than Integer.MIN_VALUE or bigger than Integer.MAX_VALUE.
More:【目录】LeetCode Java实现