Update 0474.一和零.md

Added python version code

problems/0474.一和零.md

@@ -190,7 +190,18 @@ class Solution {
 ```
 
 Python：
-
+```python
+class Solution:
+    def findMaxForm(self, strs: List[str], m: int, n: int) -> int:
+        dp = [[0] * (n + 1) for _ in range(m + 1)]
+        for str in strs:
+            oneNum = str.count('1')
+            zeroNum = str.count('0')
+            for i in range(m, zeroNum - 1, -1):
+                for j in range(n, oneNum - 1, -1):
+                    dp[i][j] = max(dp[i][j], dp[i - zeroNum][j - oneNum] + 1)
+        return dp[m][n]
+```
 
 Go：