Runtime 936 ms (Top 92.66%) | Memory 33.0 MB (Top 5.1%)

Author: AnasImloul

scripts/algorithms/L/Largest Rectangle in Histogram/Largest Rectangle in Histogram.py

@@ -1,39 +1,20 @@
-**class Solution:
-    def largestRectangleArea(self, h: List[int]) -> int:
-        stack,n=[],len(h)
-        left,right=[0]*n,[0]*n
+class Solution:
+    def largestRectangleArea(self, heights: List[int]) -> int:
+        maxArea = 0
+        stack = [] # (index, height)
 
-        for i in range(n):
-            if len(stack)==0:
-                left[i]=0
-            else:
-                while(len(stack)!=0 and h[stack[-1]]>=h[i]):
-                    stack.pop()
-                if len(stack)==0:
-                    left[i]=0
-                else:
-                    left[i]=stack[-1]+1
-            stack.append(i)
+        for i, h in enumerate(heights):
+            startIndex = i
+            while stack and stack[-1][1] > h:
+                index, height = stack.pop()
+                maxArea = max(maxArea, height * (i - index))
+                startIndex = index
+            stack.append((startIndex, h))
 
-        while(stack):
-            stack.pop()
+        
+        
+        for index, height in stack:
+            maxArea = max(maxArea, height * (len(heights) - index))
 
-        for i in range(n-1,-1,-1):
-            if len(stack)==0:
-                right[i]=n-1
-            else:
-                while(len(stack)!=0 and h[stack[-1]]>=h[i]):
-                    stack.pop()
-                if len(stack)==0:
-                    right[i]=n-1
-                else:
-                    right[i]=stack[-1]-1
-            stack.append(i)
 
-        print(left)
-        print(right)
-        
-        area=0
-        for i in range(n):
-            area=max(area,h[i]*(right[i]-left[i]+1))
-        return area**
+        return maxArea