URL: https://leetcode.com/problems/max-increase-to-keep-city-skyline/description/ direct way to solve it. use too many loops, so the speed is slow

leetcode practice.py

class Solution:
    def maxIncreaseKeepingSkyline(self, grid):
        """
        :type grid: List[List[int]]
        :rtype: int
        """
        
        # return skyline from Top or Bottom
        def fromTop(grid):
            listhori = []
            for i in range(len(grid)):
                listhori.append(max(grid[i]))
            return listhori
        
        # return skyline from Left or Right
        def fromLeft(grid):        
            listveri = []
            for i in range(len(grid)):
                name = 'list' + str(i)
                locals()[name]=[]  # use locals() to assign the changable var name
                for j in range(len(grid[0])):                                              
                    locals()[name].append(grid[j][i])
                listveri.append(max(locals()[name]))
            return listveri
        
        listhori = fromTop(grid)
        listveri = fromLeft(grid)
            
        # creat a grid
        increase = []
        for i in range(len(grid)):
            increase.append([])
            for j in range(len(grid[0])):
                increase[i].append("")
        # print (increase) debug info
                
        for i in range(len(grid)):
            for j in range(len(grid[0])):
                increase[i][j] = min(listhori[i], listveri[j]) - grid[i][j]
       
        # debug info
        #print (listhori)
        #print (listveri)
        #print (increase)
        
        sum_all = 0
        for i in range(len(increase)):
            sum_all += sum(increase[i])
        return sum_all
        
        """
        list fromTop(grid) {
            return [grid[0].max, grid[1].max, grid[2].max, grid[3].max]
        }
        
        list fromLeft(grid) {
            list1 = [grid[0][0], grid[1][0], grid[2][0],grid[3][0]]
            list2 = [grid[0][1], grid[1][1], grid[2][1],grid[3][1]]
            list3 = [grid[0][2], grid[1][2], grid[2][2],grid[3][2]]
            list4 = [grid[0][3], grid[1][3], grid[2][3],grid[3][3]]
            return [list1.max, list2.max, list3.max, list4.max]
        
        for element[i][j] in grid {
            increase[i][j] = max(listhori(i),listveri(j)) grid[2][1]
        }
        
        """