Codeforces Round #369 (Div. 2) B. Chris and Magic Square

// This is all about 311 lines code
// I am request you to please see other code if you are incapable to solve it

Accepted Code Link: B. Chris and Magic Square

//#include<stdio.h>
//#include<iostream>
//#include<algorithm>
//#include<vector>
//#include<cstring>
//#include<cmath>
//#include<map>
#include<bits/stdc++.h>
using namespace std;

#define fast ios_base::sync_with_stdio(false)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define high 505

typedef long long LL;

LL ar[high][high];
LL d=0 , diagsum1=0, diagsum2=0;
bool gotnm=false;
int n , row=0, col=0;

void checkWhole()
{
    LL rowsum=0, colsum=0, tmprow=0, tmpcol=0 , d1=0, d2=0 , ans1=0, ans2=0;
    int i,j;
    bool decision=false;

    for(i=0; i<n; i++)
    {
        rowsum=0;
        colsum=0;

        for(j=0; j<n; j++)
        {
            rowsum += ar[i][j];
            colsum += ar[j][i];
        }

        if(tmpcol==0 and tmprow==0)
        {
            tmprow = rowsum;
            tmpcol = colsum;
            //cout << rowsum << " " << tmprow << "\n" << colsum << " " << tmpcol << "; ";
        }

        else
        {
            d1 = rowsum > tmprow ? rowsum - tmprow : tmprow - rowsum;
            d2 = colsum > tmpcol ? colsum - tmpcol : tmpcol - colsum;

            if(d1 > 0)
            {
                if(rowsum > tmprow) tmprow += d1;
                else rowsum += d1;
                ans1 = d1;
            }

            if(d2 > 0)
            {
                if(colsum > tmpcol) tmpcol += d2;
                else colsum += d2;
                ans2 = d2;
            }

            //cout << rowsum << " " << tmprow << "\n" << colsum << " " << tmpcol << "; ";

//            if(tmprow != rowsum or tmpcol != colsum)
//            {
//                decision=true;
//                break;
//            }

            tmprow = rowsum;
            tmpcol = colsum;
        }
    }

    //if(decision) outn("-1");
    //cout << ans1 << " " << ans2 << "\n";
    ar[row][col] = ans2;
    tmprow=0;
    tmpcol=0;

    for(i=0; i<n; i++)
    {
        rowsum=0;
        colsum=0;

        for(j=0; j<n; j++)
        {
            rowsum+=ar[i][j];
            colsum+=ar[j][i];
        }

        if(tmprow == 0 and tmpcol==0)
        {
            tmprow = rowsum;
            tmpcol = colsum;
        }

        else
        {
            if(tmprow != rowsum or tmpcol != colsum)
            {
                decision=true;
                break;
            }

            else
            {
                tmprow = rowsum;
                tmpcol = colsum;
            }
        }
    }

    //cout << "tmprow = " << tmprow << " tmpcol = " << tmpcol;
    //cout << "des = " << decision;
    //cout << "diag1 = " << diagsum1 << " " << "diag2 = " << diagsum2;

    if(decision) cout << "-1\n";
    else
    {
        if(d == 0)
        {
            //cout << "d==0";
            diagsum1+=ar[row][col];
            diagsum2+=ar[row][col];
        }

        if((tmprow == diagsum1 and tmpcol==diagsum2) or (rowsum==diagsum1 and colsum==diagsum2))
        {
            if(ar[row][col] == 0) cout << "-1\n";
            else cout << ar[row][col] << "\n";
           // outn(ar[row][col]);
        }

        else cout << "-1\n";
    }
}

void checkRowColumn()
{
    LL rowsum=0 , colsum=0 , tmprow=0, tmpcol=0;
    int i,j;
    bool decision = false;

    for(i=0; i<n; i++)
    {
        rowsum=0;
        colsum=0;

        for(j=0; j<n; j++)
        {
            rowsum+=ar[i][j];
            colsum+=ar[j][i];
        }

        if(tmprow==0 and tmpcol==0)
        {
            tmprow = rowsum;
            tmpcol = colsum;
        }

        else
        {
            if(tmprow != rowsum or tmpcol != colsum)
            {
                decision=true;
                break;
            }

            else
            {
                tmprow = rowsum;
                tmpcol = colsum;
            }
        }
    }

    //cout << rowsum << " " << colsum << "\n";

    if(decision) outn("-1");
    else
    {
        if((tmprow == diagsum1 and tmpcol==diagsum2) or (rowsum==diagsum1 and colsum==diagsum2))
        {
            if(ar[row][col] == 0) cout << "-1\n";
            else cout << ar[row][col] << "\n";
        }

        else cout << "-1\n";
    }
}

void other()
{
    //outn("it is a other function");

    if(gotnm)
    {
        checkRowColumn();
    }

    else
    {
        //outn("gotnm false");
        checkWhole();
    }
}

int main()
{
    fast;

    while(cin >> n)
    {
        int i,j;

        if(n == 1)
        {
            cin >> ar[0][0];
            cout << "1\n";
            continue;
        }

        gotnm=false;
        d=-1;

        for(i=0; i<n; i++)
        {
            for(j=0; j<n; j++)
            {
                cin >> ar[i][j];
                if(ar[i][j] == 0)
                {
                    row=i;
                    col=j;
                }
            }
        }

        // diag 1
        //outn("diag 1");

        diagsum1 = 0;

        bool diag1zero=false, diag2zero=false;

        for(i=0; i<n; i++)
        {
            //cout << ar[i][i] << " ";
            if(ar[i][i] == 0) diag1zero=true;
            diagsum1+=ar[i][i];
        }

        // diag 2
        //outn("diag 2");

        diagsum2=0;

        for(i=0; i<n; i++)
        {
            //cout << ar[i][j] << " ";
            if(ar[i][n - i - 1] == 0) diag2zero = true;
            diagsum2+=ar[i][n - i - 1];
        }

        //cout << diag1zero << " " << diag2zero << " " << d << "\n";
        //cout << diagsum1 << " " << diagsum2 << " ";

        if(diag1zero==true or diag2zero==true)
        {
            d = diagsum1 > diagsum2 ? diagsum1 - diagsum2 : diagsum2 - diagsum1;

            if(diagsum1 > diagsum2) diagsum2 += d;
            else diagsum1 += d;
        }

        //cout << "d = " << d;
        //cout << "diagsum1 = " << diagsum1 << " diagsum2 = " << diagsum2 << " ";
        //cout << diag1zero << " " << diag2zero << "\n";

        if(diagsum1 == diagsum2)
        {
            //other();

            if(diag1zero==true or diag2zero == true)
            {
                //cout << diag1zero << " " << diag2zero << " " << d << "\n";
                //outn(d);
                if(d == 0)
                {
                    checkWhole();
                    continue;
                }
                ar[row][col] = d;
                gotnm=true;
            }

            other();
        }

        else cout << "-1\n";
    }

    return 0;
}

/*

4
1 1 1 1
1 1 0 1
1 1 1 1
1 1 1 1


*/