First Repeating Element.cpp

// Question Link: https://practice.geeksforgeeks.org/problems/first-repeating-element4018/1

class Solution{
    public:
    //Function to return the position of the first repeating element.
    int firstRepeated(int arr[], int n) {
        //code here
        unordered_map<int,int> umap;
        for(int i=0;i<n;i++)
            umap[arr[i]]++;
        for(int i=0;i<n;i++){
            int key = arr[i];
            
            auto temp = umap.find(key); 
            int val= temp->second;
            if(val >1)
                return i+1;
        }
        
        return -1;
    }
};