Dictionaries

A dictionary maps keys to values — like a real dictionary maps words to definitions. They're the go-to structure when you need to look something up by name.

What you'll learn

• Creating dictionaries with {key: value}
• Accessing values by key
• Using .get() for safe access (no crash if key is missing)
• Iterating over keys, values, and items
• Nesting dictionaries

Instructions

You'll write two small functions that the grader will test with several inputs.

1. Write count_words(words) — takes a list of words and returns a dict mapping each word to how many times it appears.
2. Write most_frequent(counts) — takes a counts dict and returns the word with the highest count. If two words tie, return the one that comes first alphabetically.
3. The starter has a driver that reads words from stdin and prints the sorted counts plus the most frequent word. Leave it as-is — it only runs when you click Run.

Example for input apple banana apple cherry banana apple:

apple: 3
banana: 2
cherry: 1
Most frequent: apple (3 times)

Key concepts

Creating and accessing:

scores = {"alice": 92, "bob": 85}
alice_score = scores["alice"]       # 92

Safe access with .get():

score = scores.get("charlie", 0)    # 0 (default, no KeyError)

Adding / updating:

scores["charlie"] = 78    # add new key
scores["alice"] = 95       # update existing key

Iterating:

for name, score in scores.items():
    print(f"{name}: {score}")

Counting pattern:

counts = {}
for word in words:
    counts[word] = counts.get(word, 0) + 1

Hints

• Split the input string with .split() (splits on whitespace by default).
• Use sorted(counts.items()) to iterate alphabetically.
• To find the max, look at max(counts, key=counts.get).