LeetCode219. Contains Duplicate II

文章目录

• • 一、题目
  • 二、题解

一、题目

Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that numsi == numsj and abs(i - j) <= 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

Constraints:

1 <= nums.length <= 105

-109 <= numsi <= 109

0 <= k <= 105

二、题解

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        int n = nums.size();
        unordered_map<int,int> map;
        for(int i = 0;i < n;i++){
            if(map.find(nums[i]) == map.end()) map[nums[i]] = i;
            else{
                if(abs(map[nums[i]] - i) <= k) return true;
                map[nums[i]] = i;
            }
        }
        return false;
    }
};