From fdac2e40b4d5fecd9b195597f89b311d5c0e4693 Mon Sep 17 00:00:00 2001
From: Azureki <fzureice@gmail.com>
Date: Sun, 9 Sep 2018 21:50:03 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E6=B3=A8=E9=87=8A?=
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---
 lc892-2.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lc892-2.py b/lc892-2.py
index e8c70d9..6e86f17 100644
--- a/lc892-2.py
+++ b/lc892-2.py
@@ -4,6 +4,9 @@ def surfaceArea(self, grid):
         :type grid: List[List[int]]
         :rtype: int
         """
+
+        # 外面，包括凹下去的。
+        # 欣宜还是考虑复杂了，负的也没关系，用绝对值就行了。不需要两个方向都跑一次。
         def helper(heights):
             cur = 0
             ret = 0
@@ -14,11 +17,14 @@ def helper(heights):
             return ret
 
         area = 0
+        # 每一行
         for row in grid:
             area += helper(row)
 
+        # 每一列
         for col in zip(*grid):
             area += helper(col)
 
+        # 上下底面
         area += sum(2 for row in grid for h in row if h > 0)
         return area