clearer variable names, added comments

brechtje/3/3-1.py

@@ -1,19 +1,27 @@
 input = open("input.txt").read().splitlines()
 
-def find_biggest_num(line, start, is_first_num):
-    num = -1
-    max_num = 9
+# line = current line that is being searched
+# start = at what index to start searching
+    # for the first digit: 0
+    # for the second digit: right after the index of the first digit
+# is_first_digit = boolean, True if first digit is being found, False if second digit is being found
+# num_to_find = (next) number to search for in the string (line), starts at 9 decreases when not found
+def find_biggest_num_index(line, start, is_first_digit):
+    index = -1
+    num_to_find = 9
     while True:
-        num = line.find(str(max_num), start)
-        if num == -1 or (is_first_num and num == len(line) - 1):
-            max_num -= 1
+        index = line.find(str(num_to_find), start)
+        # decrease num_to_find if number is not found
+        # OR we are currently searching for the first digit and the number found is the last char in the string
+        if index == -1 or (is_first_digit and index == len(line) - 1):
+            num_to_find -= 1
         else:
-            return num
+            return index
 answer = 0
 
 for line in input:
-    first_num = find_biggest_num(line, 0, True)
-    second_num = find_biggest_num(line, first_num + 1, False)
-    answer += int(line[first_num] + line[second_num])
+    first_digit_index = find_biggest_num_index(line, 0, True)
+    second_digit_index = find_biggest_num_index(line, first_digit_index + 1, False)
+    answer += int(line[first_digit_index] + line[second_digit_index])
 
 print(answer)