I have array of numbers and I have to sort them based on there frequency in ascending order
and if both numbers are same then sort them in decreasing order

what I did was I create unordered_map and store number’s frequency in map
and Inside custom sort function I used it to sort the numbers

Implemention look’s like this

class Solution {
public:
    unordered_map<int,int>map;

    bool operator ()(const int &a,const int &b){
        if(map[a]==map[b])
            return a>b;

        return map[a]<map[b];
    }

    vector<int> frequencySort(vector<int>& nums) {
        vector<int>answer;

        for(auto num:nums)
            map[num]++;

        sort(nums.begin(),nums.end(),Solution());

        return nums;
    }
};

but when I use this custom function I gives me wrong answe like

for input nums = [1,1,2,2,2,3]

output is [3,2,2,2,1,1]

which is not expected !! but functions implementation looks good

so what expexted is
Expected [3,1,1,2,2,2]

to achive this I see solution and they used lamda function for custom sorting
Implementation of lamda function is like

sort(nums.begin(),nums.end(),[&](int a, int b) {
            if (map[a] == map[b]) {
                return a > b;
            }
            return map[a] < map[b];
        });

body part of my function and lamda function is similiar
but why I am getting wrong answer ?

Thank you