Method update

src/class131/Code03_CornField.java:34–40

(int x, int y, int v)

	public static int n, k;

	public static void update(int x, int y, int v) {
		for (int i = x; i <= MAXH; i += i & -i) {
			for (int j = y; j <= k + 1; j += j & -j) {
				tree[i][j] = Math.max(tree[i][j], v);
			}
		}
	}

	public static int max(int x, int y) {
		int ans = 0;