Can anyone tell me that what is the complexity of this code. Problem Name: Maximum aera of histogram Question Link: https://leetcode.com/problems/largest-rectangle-in-histogram/

  def MAH(self,arr: List):
          
        n=len(arr)
        
        
        stackl=[]
        left=[]
        stackr=[]
        right=[]
        width=[]
        for i in range(0,n):
            
            while stackl and stackl[-1][0]>=arr[i]:
                stackl.pop()
           
                
                
            if len(stackl)==0:
                left.append(-1)
                
            else:
                left.append(stackl[-1][1])
                
            stackl.append([arr[i],i])
            
            
        for i in range(n-1,-1,-1):
            
            while stackr and stackr[-1][0]>=arr[i]:
                stackr.pop()
                
                
            if len(stackr)==0:
                right.append(n)
                
            else:
                right.append(stackr[-1][1])
                
            stackr.append((arr[i],i))

            
        right=right[::-1]
        
        
        
        for i in range(0,n):
            
            width.append(right[i]-left[i]-1)
            
            
        maxx=-9999999999999999
        
        for i in range(n):
            val =arr[i]*width[i]
            
            if val>maxx:
                maxx=val
                
        return maxx