Time limit exceeded reason in question 4 xometry

help
,
1

My issue

include <bits/stdc++.h>
using namespace std;

int main() {
// your code goes here

int t;
cin>>t;

while(t--){
    
    int n;
    cin>>n;
    
    unordered_map<int,int> mp1;
    
    vector<int> v(n);
    
    for(int i=0;i<n;i++){
        cin>>v[i];
    }
    
    for(int i=0;i<n-1;i++){
        for(int j=i+1;j<n;j++){
            
            mp1[v[i]^v[j]]++;
        }
    }
    
    long long ans = 0;
    
    for(auto it:mp1){
        
        ans += (it.second)*(it.second-1)*1ll;
    }
    
    ans = ans*4;
    
    cout<<ans<<"\n";
}

}

For question number 4 Xometry easy version above code gives TIME LIMIT EXCEEDED why?

My code

#include <bits/stdc++.h>
using namespace std;

int main() {
	// your code goes here
	
	int t;
	cin>>t;
	
	while(t--){
	    int n;
	    cin>>n;
	    
	    vector<int> v(n);
	    
	    for(int i=0;i<n;i++){
	        cin>>v[i];
	    }
	    
	    long long ans = 0;
	    
	    unordered_map<int,long long> mp;
	    
	    for(int i=0;i<n;i++){
	        for(int j=i+1;j<n;j++){
	            ans+=mp[v[i]^v[j]]++;
	        }
	    }
	    
	    cout<<ans*8*1ll<<"\n";
	}

}

Problem Link: Xometry (Easy Version) Practice Coding Problem

2

use vector instead of map
vectormp(2000000,0)
i was also getting TLE in this problem got accepted after changing map to vector

3

The problem is still the same and
Why other’s code is working?