[LeetCode] Contains Duplicate II 包含重复值之二

Given an array of integers and an integer k, return true if and only if there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. (Old Version)

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 difference between i and j is at most k. (New Version)

坑爹啊，题目要求变了，那么就没啥歧义了，正确解法如下：