[LeetCode]Contains Duplicate II

Contains Duplicate 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 difference between i and jis at most k.

和Contains Duplicate类似，多了个判断而已。

注意可能有多个重复，例如[1,0,1,1],1 为 True。

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