蛇形矩阵

gistfile1.cpp

#include <iostream>

using namespace std;

int main(int argc, char const *argv[])
{
  const int MAX = 102;
  const int STEP[4][2] = {{0, -1}, {-1, 0}, {0, 1}, {1, 0}};
  int matrix[MAX][MAX] = {0};
  int n, x, y, s = 0, sum = 0;
  cin >> n;
  x = y = n;
  for (int i = 0; i < MAX; ++i) {
    matrix[0][i] = matrix[n + 1][i] = matrix[i][0] = matrix[i][n + 1] = 1;
  }
  for (int i = n * n; i > 0; --i) {
    matrix[x][y] = i;
    if (matrix[x + STEP[s][0]][y + STEP[s][1]] && ++s == 4)
      s = 0;
    x += STEP[s][0];
    y += STEP[s][1];
  }
  for (int i = 1; i <= n; ++i) {
    for (int  j = 1; j <= n; ++j) {
      cout << matrix[i][j] << ' ';
      if (i == j || i + j == n + 1)
        sum += matrix[i][j];
    }
    cout << endl;
  }
  cout << sum;
  return 0;
}