destination-city

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Algorithms

You are given the array <code>paths</code>, where <code>paths[i] = [cityAi, cityBi]</code> means there exists a direct path going from <code>cityAi</code> to <code>cityBi</code>. Return the destination city, that is, the city without any path outgoing to another city.

It is guaranteed that the graph of paths forms a line without any loop, therefore, there will be exactly one destination city.

&nbsp;
Example 1:

<pre>
Input: paths = [[&quot;London&quot;,&quot;New York&quot;],[&quot;New York&quot;,&quot;Lima&quot;],[&quot;Lima&quot;,&quot;Sao Paulo&quot;]]
Output: &quot;Sao Paulo&quot; 
Explanation: Starting at &quot;London&quot; city you will reach &quot;Sao Paulo&quot; city which is the destination city. Your trip consist of: &quot;London&quot; -&gt; &quot;New York&quot; -&gt; &quot;Lima&quot; -&gt; &quot;Sao Paulo&quot;.
</pre>

Example 2:

<pre>
Input: paths = [[&quot;B&quot;,&quot;C&quot;],[&quot;D&quot;,&quot;B&quot;],[&quot;C&quot;,&quot;A&quot;]]
Output: &quot;A&quot;
Explanation: All possible trips are:&nbsp;
&quot;D&quot; -&gt; &quot;B&quot; -&gt; &quot;C&quot; -&gt; &quot;A&quot;.&nbsp;
&quot;B&quot; -&gt; &quot;C&quot; -&gt; &quot;A&quot;.&nbsp;
&quot;C&quot; -&gt; &quot;A&quot;.&nbsp;
&quot;A&quot;.&nbsp;
Clearly the destination city is &quot;A&quot;.
</pre>

Example 3:

<pre>
Input: paths = [[&quot;A&quot;,&quot;Z&quot;]]
Output: &quot;Z&quot;
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= paths.length &lt;= 100</code></li>
	<li><code>paths[i].length == 2</code></li>
	<li><code>1 &lt;= cityAi.length, cityBi.length &lt;= 10</code></li>
	<li><code>cityAi != cityBi</code></li>
	<li>All strings consist of lowercase and uppercase English letters and the space character.</li>
</ul>