6092. Replace elements in the array

class Solution {
public:
    vector<int> arrayChange(vector<int>& nums, vector<vector<int>>& operations) {
      //  preservation nums Subscript information of all elements in 
      // key:  value ; value:  Subscript 
      map<int, int> map;
      for(int i = 0; i < nums.size(); i++){
          //  Insert the value and the corresponding subscript 
          map.emplace(nums[i], i);
      }
      
      //  Traverse all operations 
      for(int i = 0; i < operations.size(); i++){
        auto it = map.find(operations[i][0]);
        
        //  Because it must exist , So there is no need to judge 
        // if(it == end(map)){
        //   continue;
        // }
        
        //  Replace the value of the corresponding position 
        int val = operations[i][1];
        nums[it->second] = val;
        
        //  Update or insert new elements and corresponding subscripts 
        map[val] = it->second;
      }
      
      return nums;
    }
};