March 2014 Silver Problem 2: The Lazy Cow

Result: 5/10 *****ttttt

Silver is significantly more difficult than bronze.

lazy.cpp

#include <iostream>
#include <fstream>

#define loopi(x) loop_start(i,x,0)
#define loopj(x) loop_start(j,x,0)
#define loop_start(i,x,s) for(int i = (s); i < (x); ++i)
#define loop_rev(a,x,stop) for(int a = (x); a >= (stop); --a)

using namespace std;

int main() {
 ofstream fout ("lazy.out");
 ifstream fin ("lazy.in");
 int N, K;
 fin >> N >> K;
 int *grid = new int [N * N];
 memset(grid, 0, N*N*sizeof(int));
 loopi(N)
  loopj(N)
  {
   int value;
   fin >> value;
   loop_start(x, min(i+K+1,N), max(0, i-K))
   {
    int steps_used = abs(i - x);
    loop_start(y, min(j+K+1-steps_used,N), max(0, j-K+steps_used))
    {
     grid[x * N + y] += value;
    }
   }
  }
 int maximum_value = 0;
 loopi(N)
  loopj(N)
   if(grid[i * N + j] > maximum_value)
    maximum_value = grid[i * N + j];
 fout << maximum_value << endl;
 return 0;
}