[LeetCode] 219. Contains Duplicate II 包含重复元素 II

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: true

Example 2:

Input: nums = [1,0,1,1], k = 1
Output: true

Example 3:

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

217. Contains Duplicate 的拓展, 那道题只需判断数组中是否有重复值,而这题限制了数组中只许有一组重复的数字,而且坐标差最多k。

解法: 哈希表Hash table

Java:

1
2
3
4
5
6
7
8
9
10
class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        HashMap<Integer, Integer> index = new HashMap<>();
        for (int i = 0; i < nums.length; i++) {
            if (i - index.getOrDefault(nums[i], -k - 1) <= k) return true;
            index.put(nums[i], i);
        }
        return false;
    }
} 

Python:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
class Solution:
    # @param {integer[]} nums
    # @param {integer} k
    # @return {boolean}
    def containsNearbyDuplicate(self, nums, k):
        lookup = {}
        for i, num in enumerate(nums):
            if num not in lookup:
                lookup[num] = i
            else:
                # It the value occurs before, check the difference.
                if i - lookup[num] <= k:
                    return True
                # Update the index of the value.
                lookup[num] = i
        return False  

C++:

1
2
3
4
5
6
7
8
9
10
11
class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        unordered_map<int, int> m;
        for (int i = 0; i < nums.size(); ++i) {
            if (m.find(nums[i]) != m.end() && i - m[nums[i]] <= k) return true;
            else m[nums[i]] = i;
        }
        return false;
    }
};

  

 

类似题目:

[LeetCode] 217. Contains Duplicate 包含重复元素

[LeetCode] 220. Contains Duplicate III 包含重复元素 III

   

All LeetCode Questions List 题目汇总

 

posted @   轻风舞动  阅读(464)  评论(0编辑  收藏  举报
编辑推荐:
· [.NET]调用本地 Deepseek 模型
· 一个费力不讨好的项目,让我损失了近一半的绩效!
· .NET Core 托管堆内存泄露/CPU异常的常见思路
· PostgreSQL 和 SQL Server 在统计信息维护中的关键差异
· C++代码改造为UTF-8编码问题的总结
阅读排行:
· 【.NET】调用本地 Deepseek 模型
· CSnakes vs Python.NET:高效嵌入与灵活互通的跨语言方案对比
· DeepSeek “源神”启动!「GitHub 热点速览」
· 我与微信审核的“相爱相杀”看个人小程序副业
· Plotly.NET 一个为 .NET 打造的强大开源交互式图表库
点击右上角即可分享
微信分享提示