添加 1002.查找常用字符python3版本

problems/1002.查找常用字符.md

@@ -169,6 +169,29 @@ class Solution {
     }
 }
 ```
+```python
+class Solution:
+    def commonChars(self, words: List[str]) -> List[str]:
+        if not words: return []
+        result = []
+        hash = [0] * 26 # 用来统计所有字符串里字符出现的最小频率
+        for i, c in enumerate(words[0]):  # 用第一个字符串给hash初始化
+            hash[ord(c) - ord('a')] += 1
+        # 统计除第一个字符串外字符的出现频率
+        for i in range(1, len(words)):
+            hashOtherStr = [0] * 26
+            for j in range(len(words[0])):
+                hashOtherStr[ord(words[i][j]) - ord('a')] += 1
+            # 更新hash，保证hash里统计26个字符在所有字符串里出现的最小次数
+            for k in range(26):
+                hash[k] = min(hash[k], hashOtherStr[k])
+        # 将hash统计的字符次数，转成输出形式
+        for i in range(26):
+            while hash[i] != 0: # 注意这里是while，多个重复的字符
+                result.extend(chr(i + ord('a')))
+                hash[i] -= 1
+        return result
+```
 javaScript
 ```js
 var commonChars = function (words) {