Create 0201-bitwise-and-of-numbers-range.py

Author: a93a

python/0201-bitwise-and-of-numbers-range.py

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+# check difference at each bit (cannot be more than left - right)
+class Solution:
+    def rangeBitwiseAnd(self, left: int, right: int) -> int:
+        res = 0
+
+        for i in range(32):
+            bit = (left >> i) & 1
+            if not bit:
+                continue
+            
+            remain = left % (1 << (i + 1))
+            diff = (1 << (i + 1)) - remain
+            if right - left < diff:
+                res = res | (1 << i)
+        return res
+
+# find the longest matching prefix of set bits between left and right
+class Solution:
+    def rangeBitwiseAnd(self, left: int, right: int) -> int:
+        i = 0
+        while left != right:
+            left = left >> 1
+            right = right >> 1
+            i += 1
+        return left << i