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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.
Example 1:
Input: nums = [1,2,3,1], k = 3 Output: trueExample 2:
Input: nums = [1,0,1,1], k = 1 Output: trueExample 3:
Input: nums = [1,2,3,1,2,3], k = 2 Output: false
问题描述:给定一个数组和一个整数k 判断是否存在两个重复元素i,j 使i和j的差的绝对值不大于k 如果存在 返回true 否则返回false
思路,这里使用字典Dictionary保存元素和元素的索引。如果能找到元素,则计算当前元素和上一个元素的索引的差是否不大于k
public bool ContainsNearbyDuplicate(int[] nums, int k) { Dictionary<int,int> dic = new Dictionary<int,int>(); for(int i = 0; i < nums.Length; i++){ if(dic.ContainsKey(nums[i])){ if(i - dic[nums[i]]<=k) return true; } dic[nums[i]] = i; } return false; }