<p>There is a long table with a line of plates and candles arranged on top of it. You are given a <strong>0-indexed</strong> string <code>s</code> consisting of characters <code>&#39;*&#39;</code> and <code>&#39;|&#39;</code> only, where a <code>&#39;*&#39;</code> represents a <strong>plate</strong> and a <code>&#39;|&#39;</code> represents a <strong>candle</strong>.</p>

<p>You are also given a <strong>0-indexed</strong> 2D integer array <code>queries</code> where <code>queries[i] = [left<sub>i</sub>, right<sub>i</sub>]</code> denotes the <strong>substring</strong> <code>s[left<sub>i</sub>...right<sub>i</sub>]</code> (<strong>inclusive</strong>). For each query, you need to find the <strong>number</strong> of plates <strong>between candles</strong> that are <strong>in the substring</strong>. A plate is considered <strong>between candles</strong> if there is at least one candle to its left <strong>and</strong> at least one candle to its right <strong>in the substring</strong>.</p>

<ul>
	<li>For example, <code>s = &quot;||**||**|*&quot;</code>, and a query <code>[3, 8]</code> denotes the substring <code>&quot;*||<strong><u>**</u></strong>|&quot;</code>. The number of plates between candles in this substring is <code>2</code>, as each of the two plates has at least one candle <strong>in the substring</strong> to its left <strong>and</strong> right.</li>
</ul>

<p>Return <em>an integer array</em> <code>answer</code> <em>where</em> <code>answer[i]</code> <em>is the answer to the</em> <code>i<sup>th</sup></code> <em>query</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="ex-1" src="https://assets.leetcode.com/uploads/2021/10/04/ex-1.png" style="width: 400px; height: 134px;" />
<pre>
<strong>Input:</strong> s = &quot;**|**|***|&quot;, queries = [[2,5],[5,9]]
<strong>Output:</strong> [2,3]
<strong>Explanation:</strong>
- queries[0] has two plates between candles.
- queries[1] has three plates between candles.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="ex-2" src="https://assets.leetcode.com/uploads/2021/10/04/ex-2.png" style="width: 600px; height: 193px;" />
<pre>
<strong>Input:</strong> s = &quot;***|**|*****|**||**|*&quot;, queries = [[1,17],[4,5],[14,17],[5,11],[15,16]]
<strong>Output:</strong> [9,0,0,0,0]
<strong>Explanation:</strong>
- queries[0] has nine plates between candles.
- The other queries have zero plates between candles.
</pre>

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

<ul>
	<li><code>3 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists of <code>&#39;*&#39;</code> and <code>&#39;|&#39;</code> characters.</li>
	<li><code>1 &lt;= queries.length &lt;= 10<sup>5</sup></code></li>
	<li><code>queries[i].length == 2</code></li>
	<li><code>0 &lt;= left<sub>i</sub> &lt;= right<sub>i</sub> &lt; s.length</code></li>
</ul>

class Solution:
    def platesBetweenCandles(self, s: str, queries: List[List[int]]) -> List[int]:

        n = len(s)
        prefix = [0] * n
        prefix[0] = 1 if s[0] == "*" else 0
        for i in range(1, n):
            prefix[i] = 1 if s[i] == "*" else 0
            prefix[i] += prefix[i - 1]

        left_index = [None] * n
        right_index = [None] * n

        left_index[0] = 0 if s[0] == "|" else None
        for i in range(1, n):
            if s[i] == "|":
                left_index[i] = i
            else:
                left_index[i] = left_index[i - 1]

        right_index[n - 1] = n - 1 if s[0] == "|" else None
        for i in range(n - 2, -1, -1):
            if s[i] == "|":
                right_index[i] = i
            else:
                right_index[i] = right_index[i + 1]

        # print(prefix)
        # print(left_index)
        # print(right_index)

        ans = []
        for left, right in queries:
            index1 = right_index[left]
            index2 = left_index[right]
            if index1 is None or index2 is None or index2 < index1:
                ans.append(0)
            else:
                ans.append(prefix[index2] - prefix[index1])

        return ans

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