feat(work): add Minimum Window Substring & Basic Calculator solutions and implement StockSpanner algorithm

work/1/Hard/Hash Table/76.minimum-window-substring.py

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+"""
+76. Minimum Window Substring
+Difficulty: Hard
+https://leetcode.com/problems/minimum-window-substring/
+
+──────────────────────────────────────────────────
+
+Given two strings s and t of lengths m and n respectively, return the
+minimum window substring of s such that every character in t
+(including duplicates) is included in the window. If there is no such
+substring, return the empty string "".
+
+The testcases will be generated such that the answer is unique.
+
+ 
+
+Example 1:
+
+Input: s = "ADOBECODEBANC", t = "ABC"
+Output: "BANC"
+Explanation: The minimum window substring "BANC" includes 'A', 'B',
+and 'C' from string t.
+
+Example 2:
+
+Input: s = "a", t = "a"
+Output: "a"
+Explanation: The entire string s is the minimum window.
+
+Example 3:
+
+Input: s = "a", t = "aa"
+Output: ""
+Explanation: Both 'a's from t must be included in the window.
+Since the largest window of s only has one 'a', return empty string.
+
+ 
+
+Constraints:
+
+	• m == s.length
+
+	• n == t.length
+
+	• 1 <= m, n <= 10^5
+
+	• s and t consist of uppercase and lowercase English letters.
+
+ 
+
+Follow up: Could you find an algorithm that runs in O(m + n) time?
+"""
+
+class Solution:
+    def minWindow(self, s: str, t: str) -> str:
+