# ------------------------------------------------------------
# get_country_name
# Receives a 2‑letter ISO country code and returns the
# corresponding country name.
#
# Uses a dictionary for O(1) lookups.
# Input is normalized to uppercase to ensure consistent matching.
# Returns None if the code is not found.
# ------------------------------------------------------------
def get_country_name(alpha2: str) -> str | None:
# Static lookup table; extend as needed
country_map = {
"CA": "Canada",
"CN": "China",
"DE": "Germany",
"FR": "France",
"GB": "United Kingdom",
"KR": "South Korea",
"IN": "India",
"JP": "Japan",
"US": "United States",
}
# Normalize input
code = alpha2.strip().upper()
# Lookup
return country_map.get(code)
# ------------------------------------------------------------
# main
# Demonstrates the lookup function with several sample codes.
# ------------------------------------------------------------
def main() -> None:
codes = ["US", "GB", "FR", "JP", "ZZ"] # ZZ is intentionally invalid
for code in codes:
name = get_country_name(code)
if name is not None:
print(f"{code} → {name}")
else:
print(f"{code} → (invalid code)")
if __name__ == "__main__":
main()
"""
run:
US → United States
GB → United Kingdom
FR → France
JP → Japan
ZZ → (invalid code)
"""
