220. Contains Duplicate III

Given an array of integers, find out whether there are two distinct indices i and j in the array such that the absolute difference between nums[i] and nums[j] is at most t and the absolute difference between i and j is at most k.

class Solution {
public:
bool containsNearbyAlmostDuplicate(vector<int>& nums, int k, int t) {
int n=nums.size();
if(!n)
return false;
map<long,long> tmp;
tmp[nums[0]]=0;
int j=0;
for(int i=1;i<n;i++)
{
if(i-j>k)
tmp.erase(nums[j++]);
auto a=tmp.lower_bound(nums[i]-t);
if(a!=tmp.end() && a->first<=t+nums[i])
return true;
tmp[nums[i]]=i;
}
return false;
}
};