LeetCode--220--medium--ContainDuplicateIII-优快云博客

本文链接：https://blog.youkuaiyun.com/huangdingsheng/article/details/102577233

本文介绍了解决LeetCode题目220“含近似数的判断”的方法，该题旨在查找数组中是否存在两个元素，其绝对差值不超过t且下标差不超过k。通过使用滑动窗口结合TreeSet，实现了O(nlogk)的时间复杂度。

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package com.app.main.LeetCode;

import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

/**
 * 220
 *
 * medium
 *
 * 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 t and 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
 * Created with IDEA
 * author:Dingsheng Huang
 * Date:2019/10/4
 * Time:下午8:32
 */
public class ContainDuplicateIII {

    // O(nlogk) sliding window
    public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
        TreeSet<Long> set = new TreeSet<>();

        for (int i = 0; i < nums.length; i++) {
            if (i > k) {
                set.remove((long) nums[i - k - 1]);
            }

            Long f = set.floor(((long) (nums[i])));
            Long c = set.ceiling((long) nums[i]);
            if ((f != null && (nums[i] - f) <= t) || (c != null && (c - nums[i]) <= t) ) {
                return true;
            }

            set.add((long) nums[i]);
        }

        return false;

    }
}