题目描述
题目链接:leetcode-cn.com/problems/co…
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.
实现思路
给定一个整数数组，判断其中是否存在两个不同的下标i和j满足：| nums[i] - nums[j] | <= t 并且 | i - j | <= k。
利用TreeSet ceiling操作或者floor操作，当
set.ceiling(nums[i]-t)<=nums[i]+t 则必然set中必然存在一个nums[j] 使得 nums[i] - nums[j] | <= t。
同时我们利用维护一个大小为 k的滑动窗口，遍历数组即可。
程序实现
public class Solution {
public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
if(k<1||t<0)
return false;
TreeSet<Long> set=new TreeSet<Long>();
for(int i=0;i<nums.length;i++){
if(set.ceiling((long)nums[i]-(long)t)!=null && set.ceiling((long)nums[i]-(long)t)<=(long)nums[i]+(long)t)
return true;
set.add((long)nums[i]);
//保持set中最多有k个元素
if(i>=k)
set.remove((long)nums[i-k]);
}
return false;
}
}
