<p>You are playing a game involving a <strong>circular</strong> array of non-zero integers <code>nums</code>. Each <code>nums[i]</code> denotes the number of indices forward/backward you must move if you are located at index <code>i</code>:</p>
<ul>
<li>If <code>nums[i]</code> is positive, move <code>nums[i]</code> steps <strong>forward</strong>, and</li>
<li>If <code>nums[i]</code> is negative, move <code>nums[i]</code> steps <strong>backward</strong>.</li>
</ul>
<p>Since the array is <strong>circular</strong>, you may assume that moving forward from the last element puts you on the first element, and moving backwards from the first element puts you on the last element.</p>
<p>A <strong>cycle</strong> in the array consists of a sequence of indices <code>seq</code> of length <code>k</code> where:</p>
<ul>
<li>Following the movement rules above results in the repeating index sequence <code>seq[0] -> seq[1] -> ... -> seq[k - 1] -> seq[0] -> ...</code></li>
<li>Every <code>nums[seq[j]]</code> is either <strong>all positive</strong> or <strong>all negative</strong>.</li>
<li><code>k > 1</code></li>
</ul>
<p>Return <code>true</code><em> if there is a <strong>cycle</strong> in </em><code>nums</code><em>, or </em><code>false</code><em> otherwise</em>.</p>
<strong>Explanation:</strong> The graph shows how the indices are connected. White nodes are jumping forward, while red is jumping backward.
We can see the cycle 0 --> 1 --> 0 --> ..., and while it is of size > 1, it has a node jumping forward and a node jumping backward, so <strong>it is not a cycle</strong>.
We can see the cycle 3 --> 4 --> 3 --> ..., and all of its nodes are white (jumping in the same direction).
