Description

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

分析

题目的意思是:给你一个数组,然后给定一个k,问数组里面是否存在两个一样的数,并且间隔最大为k。

  • 没想到用一个hash表存储每个值的索引,然后在遍历的时候判断一下间隔就行了。

代码

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

参考文献

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