validate-stack-sequences.md

<p>Given two sequences <code>pushed</code> and <code>popped</code>&nbsp;<strong>with distinct values</strong>,&nbsp;return <code>true</code> if and only if this could have been the result of a sequence of push and pop operations on an initially empty stack.</p>

<p>&nbsp;</p>

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<p><strong>Example 1:</strong></p>

<pre>
<strong>Input: </strong>pushed = <span id="example-input-1-1">[1,2,3,4,5]</span>, popped = <span id="example-input-1-2">[4,5,3,2,1]</span>
<strong>Output: </strong><span id="example-output-1">true</span>
<strong>Explanation: </strong>We might do the following sequence:
push(1), push(2), push(3), push(4), pop() -&gt; 4,
push(5), pop() -&gt; 5, pop() -&gt; 3, pop() -&gt; 2, pop() -&gt; 1
</pre>

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<p><strong>Example 2:</strong></p>

<pre>
<strong>Input: </strong>pushed = <span id="example-input-2-1">[1,2,3,4,5]</span>, popped = <span id="example-input-2-2">[4,3,5,1,2]</span>
<strong>Output: </strong><span id="example-output-2">false</span>
<strong>Explanation: </strong>1 cannot be popped before 2.
</pre>

<p>&nbsp;</p>

<p><strong>Note:</strong></p>

<ol>
	<li><code>0 &lt;= pushed.length == popped.length &lt;= 1000</code></li>
	<li><code>0 &lt;= pushed[i], popped[i] &lt; 1000</code></li>
	<li><code>pushed</code> is a permutation of <code>popped</code>.</li>
	<li><code>pushed</code> and <code>popped</code> have distinct values.</li>
</ol>
</div>
</div>