Leetcode 219. duplicate Element II exists (yes, resolved)

Give you an array of integers nums And an integer k , Determine whether there are two... In the array Different indexes i and j , Satisfy nums[i] == nums[j] And abs(i - j) <= k . If there is , return true ; otherwise , return false .

Example 1：

 Input ：nums = [1,2,3,1], k = 3
 Output ：true

Example 2：

 Input ：nums