Runtime 2166 ms (Top 33.66%) | Memory 30.0 MB (Top 17.31%)

Author: AnasImloul

scripts/algorithms/S/Smallest Subarrays With Maximum Bitwise OR/Smallest Subarrays With Maximum Bitwise OR.py

@@ -0,0 +1,35 @@
+class Solution:
+    def smallestSubarrays(self, nums: List[int]) -> List[int]:
+        # two sweeps
+        len_n = len(nums)
+        # sweep 1: find the maximum OR value at each index
+        max_or = [0] * len_n
+        idx, c_or = len_n - 1, 0
+        while idx >= 0:
+            c_or |= nums[idx]
+            max_or[idx] = c_or
+            idx -= 1
+        
+        # sweep 2: starting from the last number, track the closest index for every bit
+        ans = [1] * len_n
+        bidx = [None] * 32
+        idx = len_n - 1
+        while idx >= 0:
+            i = 0
+            n = nums[idx]
+            while n:
+                if n & 1:
+                    bidx[i] = idx
+                i += 1
+                n >>= 1
+            mor = max_or[idx]
+            max_dist, i = 1, 0
+            while mor:
+                if mor & 1:
+                    max_dist = max(max_dist, bidx[i] - idx + 1)
+                i += 1
+                mor >>= 1
+            ans[idx] = max_dist
+            idx -= 1
+            
+        return ans