#include using namespace std; #define maxn 20 int a[maxn][maxn]; //蛇型填数 int main() { int n, x, y, tot = 0; scanf("%d", &n); memset(a, 0, sizeof(a)); tot = a[x = 0][y = n - 1] = 1; while (tot < n * n) { while (x + 1 < n && !a[x + 1][y]) a[++x][y] = ++tot; while (y - 1 >= 0 && !a[x][y - 1]) a[x][--y] = ++tot; while (x - 1 >= 0 && !a[x - 1][y]) a[--x][y] = ++tot; while (y + 1 < n && !a[x][y + 1]) a[x][++y] = ++tot; } for (x = 0; x < n; x++) { for (y = 0; y < n; y++) printf("%3d", a[x][y]); printf("\n"); } return 0; }