adding algo

src/my_project/interviews/google_top_exercises/round_1/10_minimum_window_substring.py

@@ -0,0 +1,30 @@
+from collections import Counter
+
+class Solution:
+    def minWindow(self, s: str, t: str) -> str:
+        if not s or not t or len(s) < len(t):
+            return ""
+
+        need = Counter(t)          # chars (with counts) still required
+        missing = len(t)           # total chars still to satisfy
+        left = 0
+        best_left, best_len = 0, float("inf")
+
+        for right, char in enumerate(s):
+            # This char helps only if we still need it (count > 0)
+            if need[char] > 0:
+                missing -= 1
+            need[char] -= 1
+
+            # Window covers all of t: try to shrink from the left
+            while missing == 0:
+                if right - left + 1 < best_len:
+                    best_left, best_len = left, right - left + 1
+
+                need[s[left]] += 1
+                # Dropping this char breaks coverage only if it was required
+                if need[s[left]] > 0:
+                    missing += 1
+                left += 1
+
+        return "" if best_len == float("inf") else s[best_left:best_left + best_len]