Create smallest-subarray-to-sort-in-every-sliding-window.py

Author: kamyu104

Python/smallest-subarray-to-sort-in-every-sliding-window.py

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+# Time:  O(n)
+# Space: O(n)
+
+# mono stack, two pointers
+class Solution(object):
+    def minSubarraySort(self, nums, k):
+        """
+        :type nums: List[int]
+        :type k: int
+        :rtype: List[int]
+        """
+        def count(nums):
+            nxt, stk = [n]*n, []
+            for i in reversed(xrange(n)):
+                while not (not stk or nums[stk[-1]] >= nums[i]):
+                    stk.pop()
+                if stk:
+                    nxt[i] = stk[-1]
+                stk.append(i)
+            result = []
+            j, left = 0, -1
+            for i in xrange(1, n):
+                if nums[i] < nums[i-1]:
+                    left = i
+                if i < k-1:
+                    continue
+                j = max(j, i-(k-1))
+                while not nxt[j] > left:
+                    j = nxt[j]  # or j += 1
+                result.append(max(i-nxt[j]+1, 0))
+            return result
+
+        n = len(nums)
+        if k == 1:
+            return [0]*(n-k+1)
+        right = count(nums)
+        for i in xrange((n+1)//2):
+            nums[i], nums[~i] = -nums[~i], -nums[i]
+        left = count(nums)
+        return [max(k-left[~i]-right[i], 0) for i in xrange(n-k+1)]