std::vector<int>Sort(std::vector<int>&arr)
{
assert(!arr.empty());
std::unordered_map<int, int>freqMap;
for (auto it : arr)
{
auto iter = freqMap.find(it);
if (iter != freqMap.end())
{
freqMap[it]++;
}
else
freqMap[it] = 1;
}
std::sort(arr.begin(), arr.end(), [&freqMap](int
lhs, int rhs){
return freqMap.at(lhs) > freqMap.at(rhs);
});
return arr;
}
