<p>Given a string s represents the serialization of a nested list, implement a parser to deserialize it and return <em>the deserialized</em> <code>NestedInteger</code>.</p>

<p>Each element is either an integer or a list whose elements may also be integers or other lists.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;324&quot;
<strong>Output:</strong> 324
<strong>Explanation:</strong> You should return a NestedInteger object which contains a single integer 324.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;[123,[456,[789]]]&quot;
<strong>Output:</strong> [123,[456,[789]]]
<strong>Explanation:</strong> Return a NestedInteger object containing a nested list with 2 elements:
1. An integer containing value 123.
2. A nested list containing two elements:
    i.  An integer containing value 456.
    ii. A nested list with one element:
         a. An integer containing value 789
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 5 * 10<sup>4</sup></code></li>
	<li><code>s</code> consists of digits, square brackets <code>&quot;[]&quot;</code>, negative sign <code>&#39;-&#39;</code>, and commas <code>&#39;,&#39;</code>.</li>
	<li><code>s</code> is the serialization of valid <code>NestedInteger</code>.</li>
	<li>All the values in the input are in the range <code>[-10<sup>6</sup>, 10<sup>6</sup>]</code>.</li>
</ul>

# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
#class NestedInteger:
#    def __init__(self, value=None):
#        """
#        If value is not specified, initializes an empty list.
#        Otherwise initializes a single integer equal to value.
#        """
#
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def add(self, elem):
#        """
#        Set this NestedInteger to hold a nested list and adds a nested integer elem to it.
#        :rtype void
#        """
#
#    def setInteger(self, value):
#        """
#        Set this NestedInteger to hold a single integer equal to value.
#        :rtype void
#        """
#
#    def getInteger(self):
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None if this NestedInteger holds a nested list
#        :rtype int
#        """
#
#    def getList(self):
#        """
#        @return the nested list that this NestedInteger holds, if it holds a nested list
#        Return None if this NestedInteger holds a single integer
#        :rtype List[NestedInteger]
#        """

class Solution:
    def deserialize(self, s: str) -> NestedInteger:
        # tree = NestedInteger()
        tree = None
        flat = s.split(',')
        
        #depth_q = [tree]
        depth_q = []
        for el in flat:
            # if depth_q[-1] == tree and ('[' not in el):
            if len(depth_q) == 0 and ('[' not in el):
                # only top level
                # tree.setInteger(int(el))
                return NestedInteger(value=int(el))

            # [789]]], or [[[[-10],
            i = 0
            while el[i] == '[':
                lower_level = NestedInteger()
                if len(depth_q) > 0:
                    depth_q[-1].add(lower_level)
                depth_q.append(lower_level)
                i += 1
            value = []
            while i < len(el) and el[i] != ']':
                value.append(el[i])
                i += 1

            if len(value) > 0:
                value = int(''.join(value))
                depth_q[-1].add(NestedInteger(value=value))
            
            while i < len(el) and el[i] == ']':
                tree = depth_q.pop()
                i += 1            

            # go up the queue
        return tree
19700