update

Author: genkimaru

stack/largest_rectangle_area.py

@@ -0,0 +1,23 @@
+from typing  import List
+
+## 暴力法
+def largest_rectangle_area(heights : List[int]) -> int:
+    if not heights:
+        return 0
+    
+    max_area = 0
+    for i in range(len(heights)):
+        right_i = i 
+        left_i = i
+        while right_i < len(heights) - 1 and heights[right_i + 1]  >= heights[i] :
+            right_i += 1
+        while left_i > 0 and heights[left_i - 1 ] >= heights[i]:
+            left_i -= 1
+        max_area = max(max_area , ( right_i - left_i + 1 ) * heights[i])
+    
+    return max_area
+
+heights = [2,1,5,6,2,3]
+print(largest_rectangle_area(heights))
+        
+

stack/largest_rectangle_area_v2.py

@@ -0,0 +1,30 @@
+from typing  import List
+
+## 利用单调Stack 
+def largest_rectangle_area(heights):
+    stack = []
+    max_area = 0
+    index = 0
+
+    while index < len(heights):
+        if not stack or heights[stack[-1]] <= heights[index]:
+            stack.append(index)
+            index += 1
+        else:
+            top_index = stack.pop()
+            area = heights[top_index] * (index - stack[-1] - 1 if stack else index)
+            max_area = max(max_area, area)
+
+    while stack:
+        top_index = stack.pop()
+        area = heights[top_index] * (index - stack[-1] - 1 if stack else index)
+        max_area = max(max_area, area)
+
+    return max_area
+
+
+
+heights = [2,1,5,6,2,3]
+print(largest_rectangle_area(heights))
+        
+