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.
提示:提交代码后,需要用简洁的语言解释一下代码思路~ 谢谢
历史题目和总结见公众号「每日一道算法题」
https://leetcode.com/problems/contains-duplicate-ii/description/
思路: