Leetcode 1331 array sequence number conversion [map] the leetcode path of heroding

Their thinking ：
Sort the array , Map with a hash table to get the sequence number corresponding to each number , Then re traverse the array and replace the elements in the array , The code is as follows ：

class Solution {
    
public:
    vector<int> arrayRankTransform(vector<int>& arr) {
    
        vector<int> temp = arr;
        sort(temp.begin(), temp.end());
        unordered_map<int, int> mp;
        for(auto& t : temp) {
    
            if(!mp.count(t)) {
    
                mp[t] = mp.size() + 1;
            }
        }
        for(int i = 0; i < arr.size(); i ++) {
    
            arr[i] = mp[arr[i]];
        }
        return arr;
    }
};