Solution of codeforces round 342C

#include<bits/stdc++.h>
using namespace std;
#define maxn 500

int main()
{
    int mat[maxn+5][maxn+5], n, k, sum=0;
    scanf("%d %d", &n, &k);
    int row = n;
    int value = n*n;
    int fixed = (n-k)+1;
    int leftvalue = value-(fixed*n);

//    cout << " fixed = " << fixed << " leftvalue = " << leftvalue << endl;

//    cout << " row " <<

    while(row > 0){
        for(int i=0, k=n; i<fixed; ++i, --k, --value){
            mat[row][k] = value;
//            cout << " mat[ " << row << " ][ " << k << " ] = " << mat[row][k] << " ";

        }
//        cout << endl;
        for(int i=n-fixed; i>0; --i, --leftvalue){
            mat[row][i] = leftvalue;
//            cout << " mat[ " << row << " ][ " << i << " ] = " << mat[row][i] << " ";
        }
//        cout << endl;
        --row;
    }

    for(int i=1; i<=n; ++i){
        sum += mat[i][k];
    }

    printf("%d\n", sum);

    for(int i=1; i<=n; ++i){
        for(int j=1; j<=n; ++j)
            printf("%d ", mat[i][j]);
        printf("\n");
    }



    return 0;
}