ord and enumerate. lower is cool :love:

Leet_Code/easy/171_excel_sheet_column_number.py

@@ -0,0 +1,21 @@
+# my first approach
+class Solution:
+    def titleToNumber(self, columnTitle: str) -> int:
+        result = 0
+
+        j = 1
+        for i in range(len(columnTitle)-1, -1, -1):
+            # result = ord(f"{columnTitle[i].lower()}") * j
+            result += (ord(columnTitle[i].lower()) - ord('a') + 1) * j
+            j *= 26
+
+        return result
+
+# fast and clean
+class Solution:
+    def titleToNumber(self, columnTitle: str) -> int:
+        out = 0
+        for i, x in enumerate(columnTitle[::-1]):
+            out += (ord(x) - 64) * 26**i
+
+        return out