LeetCode helper methods for console debugging

LimitOutput.java

static {
    System.setOut(new java.io.PrintStream(new java.io.FilterOutputStream(System.out) {
  		int count = 10 * 1024;
  		@Override public void write(int b) throws IOException {
  			if (count > 0) {
  				super.write(b);
  				--count;
  			}
  		}
  		@Override public void write(byte[] b, int off, int len) throws IOException {
  			if (count > 0) {
  				len = Math.min(count, len);
  				super.write(b, off, len);
  				count -= len;
  			}
  		}
  	}));
}

ListNode.java

private static String val(ListNode node) {
    return node != null ? String.valueOf(node.val) : "null";
}
private static String list(ListNode head) {
    return list("", head, -1);
}
private static String list(ListNode head, int k) {
    return list("", head, k);
}
private static String list(String label, ListNode head) {
    return list(label, head, -1);
}
private static String list(String label, ListNode head, int k) {
    StringBuilder sb = new StringBuilder();
    sb.append(label).append("[");
    ListNode slow = head;
    ListNode fast = head;
    while (slow != null) {
        sb.append(val(slow));
        if (slow.next != null) {
            sb.append(", ");
        }
        if (--k == 0) {
            if (slow.next != null) sb.append("...");
            break;
        }
        slow = slow.next;
        fast = fast != null && fast.next != null? fast.next.next : null;
        if (fast != null && slow == fast) {
            slow = head;
            while (slow != fast) {
                sb.append(val(fast));
                if (fast.next != null) {
                    sb.append(", ");
                }
                slow = slow.next;
                fast = fast.next;
            }
            sb.append("cycle from ");
            sb.append(val(slow));
            break;
        }
    }
    sb.append("]");
    return sb.toString();
}