findMissing.txt

Find Missing And Repeating

Given an unsorted array Arr of size N of positive integers. One number 'A' from set {1, 2,....,N}
is missing and one number 'B' occurs twice in array.
Find these two numbers.

class Solution{
public:
    int returnMissing(vector<int>arr,int n){
        unordered_map<int,bool>mp;
        
        for(int i=1; i<=n; i++){
            mp[i] = false;
        }
        for(int i=0; i<arr.size(); i++){
            mp[arr[i]] = true;
        }
        for(auto i:mp){
            if(i.second ==false){
                return i.first;
            }
        }
        return 0;
    }
    
    int returnDuplicate(vector<int>arr,int n){
        unordered_map<int,int>mp;
        for(int i=0; i<n; i++){
            mp[arr[i]]++;
        }
        for(auto i:mp){
            if(i.second > 1){
                return i.first;
            }
        }
        return 0;
    }
    
    vector<int> findTwoElement(vector<int> arr, int n) {
        vector<int>ans;
        int repeat = returnDuplicate(arr,n);
        int missing = returnMissing(arr,n);
        ans.push_back(repeat);
        ans.push_back(missing);
        return ans;
    }
};