Add solution for day 1

day1/part1.py

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+"""
+--- Day 1: Calorie Counting ---
+
+Santa's reindeer typically eat regular reindeer food, but they need a
+lot of magical energy to deliver presents on Christmas. For that, their
+favorite snack is a special type of star fruit that only grows deep in
+the jungle. The Elves have brought you on their annual expedition to
+the grove where the fruit grows.
+
+To supply enough magical energy, the expedition needs to retrieve a
+minimum of fifty stars by December 25th. Although the Elves assure you
+that the grove has plenty of fruit, you decide to grab any fruit you
+see along the way, just in case.
+
+Collect stars by solving puzzles. Two puzzles will be made available on
+each day in the Advent calendar; the second puzzle is unlocked when you
+complete the first. Each puzzle grants one star. Good luck!
+
+The jungle must be too overgrown and difficult to navigate in vehicles
+or access from the air; the Elves' expedition traditionally goes on
+foot. As your boats approach land, the Elves begin taking inventory of
+their supplies. One important consideration is food - in particular,
+the number of Calories each Elf is carrying (your puzzle input).
+
+The Elves take turns writing down the number of Calories contained by
+the various meals, snacks, rations, etc. that they've brought with
+them, one item per line. Each Elf separates their own inventory from
+the previous Elf's inventory (if any) by a blank line.
+
+For example, suppose the Elves finish writing their items' Calories and
+end up with the following list:
+
+1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000
+
+This list represents the Calories of the food carried by five Elves:
+
+- The first Elf is carrying food with 1000, 2000, and 3000 Calories, a
+  total of 6000 Calories.
+- The second Elf is carrying one food item with 4000 Calories.
+- The third Elf is carrying food with 5000 and 6000 Calories, a total
+  of 11000 Calories.
+- The fourth Elf is carrying food with 7000, 8000, and 9000 Calories, a
+  total of 24000 Calories.
+- The fifth Elf is carrying one food item with 10000 Calories.
+
+In case the Elves get hungry and need extra snacks, they need to know
+which Elf to ask: they'd like to know how many Calories are being
+carried by the Elf carrying the most Calories. In the example above,
+this is 24000 (carried by the fourth Elf).
+
+Find the Elf carrying the most Calories. How many total Calories is
+that Elf carrying?
+"""
+
+
+def main():
+    with open("input.txt", "r", encoding="utf-8") as f:
+        calories_per_elf = [0]
+
+        for line in f:
+            if line.strip():
+                calories_per_elf[-1] += int(line.strip())
+            else:
+                calories_per_elf.append(0)
+                continue
+
+    highest_calories = max(*calories_per_elf)
+    index_of_highest = calories_per_elf.index(highest_calories)
+
+    print(f"Elf #{index_of_highest+1} is carrying {highest_calories} calories")
+
+
+if __name__ == "__main__":
+    main()

day1/part2.py

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+"""
+--- Part Two ---
+
+By the time you calculate the answer to the Elves' question, they've
+already realized that the Elf carrying the most Calories of food might
+eventually run out of snacks.
+
+To avoid this unacceptable situation, the Elves would instead like to
+know the total Calories carried by the top three Elves carrying the
+most Calories. That way, even if one of those Elves runs out of snacks,
+they still have two backups.
+
+In the example above, the top three Elves are the fourth Elf (with
+24000 Calories), then the third Elf (with 11000 Calories), then the
+fifth Elf (with 10000 Calories). The sum of the Calories carried by
+these three elves is 45000.
+
+Find the top three Elves carrying the most Calories. How many Calories
+are those Elves carrying in total?
+"""
+
+
+def main():
+    with open("input.txt", "r", encoding="utf-8") as f:
+        calories_per_elf = [0]
+
+        for line in f:
+            if line.strip():
+                calories_per_elf[-1] += int(line.strip())
+            else:
+                calories_per_elf.append(0)
+                continue
+
+    total_highest_calories = 0
+    highest_calories = max(*calories_per_elf)
+    index_of_highest = calories_per_elf.index(highest_calories)
+    i = 3
+    while i > 0:
+        total_highest_calories += calories_per_elf[index_of_highest]
+        calories_per_elf.pop(index_of_highest)
+        highest_calories = max(*calories_per_elf)
+        index_of_highest = calories_per_elf.index(highest_calories)
+        i -= 1
+
+    print(f"The three elves carrying the most calories together have {total_highest_calories} calories")
+
+
+if __name__ == "__main__":
+    main()

day1/testinput.txt

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+1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000