uploaded solution for 1671

Author: choppystick

Daily Problems/Hard/1671. Minimum Number of Removals to Make Mountain Array/solution.py

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+from bisect import *
+
+class Solution:
+    def minimumMountainRemovals(self, nums: list[int]) -> int:
+        n = len(nums)
+        
+        # Calculate LIS from the left side
+        left_lis = [0] * n
+        temp = []
+        for i in range(n):
+            pos = bisect_left(temp, nums[i])
+            if pos == len(temp):
+                temp.append(nums[i])
+            else:
+                temp[pos] = nums[i]
+            left_lis[i] = pos + 1
+        
+        # Calculate LIS from the right side (for LDS)
+        right_lis = [0] * n
+        temp = []
+        for i in range(n - 1, -1, -1):
+            pos = bisect_left(temp, nums[i])
+            if pos == len(temp):
+                temp.append(nums[i])
+            else:
+                temp[pos] = nums[i]
+            right_lis[i] = pos + 1
+        
+        # Calculate the maximum mountain length
+        max_mountain = 0
+        for i in range(1, n - 1):
+            if left_lis[i] >= 2 and right_lis[i] >= 2:
+                max_mountain = max(max_mountain, left_lis[i] + right_lis[i] - 1)
+        
+        # Return minimum elements to remove
+        return n - max_mountain if max_mountain > 0 else n