1649C - Weird Sum - CodeForces Solution

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

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int n,m,x;
    cin >> n >> m;

    map<int, vector< int > >  a;
    map<int, vector< int > >  b;

    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> x;
            a[x].push_back(i);
            b[x].push_back(j);
        }
    }

    map<int, vector< int > > :: iterator i;

    for (i = a.begin(); i != a.end(); i++)
    {
        sort(i->second.begin(),i->second.end());
    }
        for (i = b.begin(); i != b.end(); i++)
    {
        sort(i->second.begin(),i->second.end());
    }

    int l,s1=0,s2=0;

    for (i = a.begin(); i != a.end(); i++)
    {
        l=i->first;
        for (int j = 0; j< a[l].size()-1 ; j++)
        {
            s1+= (a[l][j+1] - a[l][j])*(j+1)*(a[l].size()-1-j);
        }
    }
    for (i = b.begin(); i != b.end(); i++)
    {
        l=i->first;
        for (int j = 0; j< b[l].size()-1 ; j++)
        {
            s2+= (b[l][j+1] - b[l][j])*(j+1)*(b[l].size()-1-j);
        }
    }

    cout<<s1+s2<<endl;
}