Merge pull request #2748 from zhihali/master

增加py的dp解法到 53.最大子序和，并添加缺失标题

problems/0053.最大子序和.md

@@ -214,6 +214,7 @@ class Solution:
         return result
 
 ```
+贪心法
 ```python
 class Solution:
     def maxSubArray(self, nums):
@@ -226,8 +227,18 @@ class Solution:
             if count <= 0:  # 相当于重置最大子序起始位置，因为遇到负数一定是拉低总和
                 count = 0
         return result
-
-
+```
+动态规划
+```python
+class Solution:
+    def maxSubArray(self, nums: List[int]) -> int:
+        dp = [0] * len(nums)
+        dp[0] = nums[0]
+        res = nums[0]
+        for i in range(1, len(nums)):
+            dp[i] = max(dp[i-1] + nums[i], nums[i])
+            res = max(res, dp[i])
+        return res
 ```
 ### Go
 贪心法