LintCode "Sliding Window Median" & "Data Stream Median"

class Solution {
void removeOnly1(multiset<int> &ms, int v)
{
auto pr = ms.equal_range(v);
ms.erase(pr.first);
}

void remove(multiset<int> &lmax, multiset<int> &rmin, int v)
{
if(v <= *lmax.rbegin())
{
removeOnly1(lmax, v);
if(lmax.size() < rmin.size())
{
int tmp = *rmin.begin();
lmax.insert(tmp);
removeOnly1(rmin, tmp);
}
}
else if(v >= *rmin.begin())
{
removeOnly1(rmin, v);
if((lmax.size() - rmin.size()) > 1)
{
int tmp = *lmax.rbegin();
removeOnly1(lmax, tmp);
rmin.insert(tmp);
}
}
}

void addin(multiset<int> &lmax, multiset<int> &rmin, int v)
{
if(lmax.empty())
{
lmax.insert(v);
return;
}
int lmax_v = *lmax.rbegin();
int size_l = lmax.size(), size_r = rmin.size();
if(v <= lmax_v) // to add left
{
lmax.insert(v);
if((size_l + 1 - size_r) > 1)
{
int tmp = *lmax.rbegin();
rmin.insert(tmp);
removeOnly1(lmax, tmp);
}
}
else
{
rmin.insert(v);
if((size_r  + 1)> size_l)
{
int tmp = *rmin.begin();
removeOnly1(rmin, tmp);
lmax.insert(tmp);
}
}
}
public:
/**
* @param nums: A list of integers.
* @return: The median of the element inside the window at each moving
*/
vector<int> medianSlidingWindow(vector<int> &nums, int k) {
vector<int> ret;

multiset<int> lmax, rmin; // sizeof(lmax) - sizeof(rmin) -> [0,1]

size_t n = nums.size();
for(int i = 0; i < n; i ++)
{
if(i >= k)
{
remove(lmax, rmin, nums[i - k]);
}

//
addin(lmax, rmin, nums[i]);
//
if(i >= k - 1)
{
ret.push_back(*lmax.rbegin());
}
}
return ret;
}
};