freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/698a1a73ade5ac0e19180fa0.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
698a1a73ade5ac0e19180fa0	Challenge 197: Blood Type Compatibility	29	challenge-197

--description--

Given a donor blood type and a recipient blood type, determine whether the donor can give blood to the recipient.

Each blood type consists of:

• A letter: "A", "B", "AB", or "O"
• And an Rh factor: "+" or "-"

Blood types will be one of the valid letters followed by an Rh factor. For example, "AB+" and "O-" are valid blood types.

Letter Rules:

• "O" can donate to other letter type.
• "A" can donate to "A" and "AB".
• "B" can donate to "B" and "AB".
• "AB" can donate only to "AB".

Rh Rules:

• Negative ("-") can donate to both "-" and "+".
• Positive ("+") can donate only to "+".

Both letter and Rh rule must pass for a donor to be able to donate to the recipient.

--hints--

can_donate("B+", "B+") should return True.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("B+", "B+"), True)`)
}})

can_donate("O-", "AB-") should return True.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("O-", "AB-"), True)`)
}})

can_donate("O+", "A-") should return False.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("O+", "A-"), False)`)
}})

can_donate("A+", "AB+") should return True.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("A+", "AB+"), True)`)
}})

can_donate("A-", "B-") should return False.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("A-", "B-"), False)`)
}})

can_donate("B-", "AB+") should return True.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("B-", "AB+"), True)`)
}})

can_donate("B-", "A+") should return False.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("B-", "A+"), False)`)
}})

can_donate("O-", "O+") should return True.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("O-", "O+"), True)`)
}})

can_donate("O+", "O-") should return False.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("O+", "O-"), False)`)
}})

can_donate("AB+", "AB-") should return False.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertIs(can_donate("AB+", "AB-"), False)`)
}})

--seed--

--seed-contents--

def can_donate(donor, recipient):

    return donor

--solutions--

def can_donate(donor, recipient):
    donor_type = donor[:-1]
    donor_rh = donor[-1]

    recipient_type = recipient[:-1]
    recipient_rh = recipient[-1]

    abo_compatibility = {
        "O": ["A", "B", "AB", "O"],
        "A": ["A", "AB"],
        "B": ["B", "AB"],
        "AB": ["AB"]
    }

    abo_match = recipient_type in abo_compatibility[donor_type]
    rh_match = (
        donor_rh == "-" or
        (donor_rh == "+" and recipient_rh == "+")
    )

    return abo_match and rh_match