counting sort with negative numbers

counting_sort.cpp

#include <iostream>
#include <vector>
#include <unordered_map>
#include <limits>

void counting_sort(vector<int> &v)
{
    int n = v.size();
    unordered_map<int, int> map;

    int min = numeric_limits<int>::max();
    int max = numeric_limits<int>::min();

    for (auto &item : v)
    {
        if (item > max)
            max = item;
        if (item < min)
            min = item;

        auto got = map.find(item);
        if (got == map.end())
        {
            map[item] = 0;
        }
        map[item]++;
    }

    int counter = 0;
    for (int i = min; i <= max; i++)
    {
        auto cur = map.find(i);
        if (cur != map.end())
        {
            for (int k = 0; k < cur->second; k++)
            {
                v[counter++] = cur->first;
            }
        }
    }
}