Confluent — Software Engineer ❌ Failed

Level: Senior-Level

Round: Phone Screen · Type: Coding · Difficulty: 5/10 · Duration: 60 min · Interviewer: Neutral

Topics: Data Structures, Algorithms, Function Overloading

Location: San Francisco Bay Area

Interview date: 2025-12-07

Got offer: False

Summary

I had a phone screen where I was asked to design a registry system for function overloads, similar to C++/Python dispatch. The functions have a name, argument type list, and possibly isVariadic. I needed to implement register() to store the functions and find_matches() to return all functions whose argument signatures match (or can match via variadic args).

Details

The coding question was:

` register([ funA: {["Boolean", "Integer"]}, funB: {["Integer"]}, funC: {["Integer"]} ])

find_matches(["Boolean", "Integer"]) -> [funA] find_matches(["Integer"]) -> [funB, funC] `

` class Function(object): def init(self, name, argument_types): self.name = name self.argument_types = argument_types

def __repr__(self):
    return f"Function<{self.name}>"

class FunctionLibrary(object): def init(self): pass # TODO

def register(self, list_of_functions):
    pass  # TODO

def find_matches(self, argument_types):
    pass  # TODO

Some tests

flib = FunctionLibrary() flib.register([ Function("funA", ["Boolean", "Integer"]), Function("funB", ["Integer"]), Function("funC", ["Integer"]) ])

assert flib.find_matches(["Boolean", "Integer"]) == ["funA"] assert flib.find_matches(["Integer"]) == ["funB", "funC"] `

Extended Version (with isVariadic support)

` """ register([ funA: {["Boolean", "Integer"], isVariadic: False}, funB: {["Integer"], isVariadic: False}, funC: {["Integer"], isVariadic: True} ])

findMatches(["Boolean", "Integer"]) -> [funA] findMatches(["Integer"]) -> [funB, funC] findMatches(["Integer", "Integer", "Integer"]) -> [funC] """

class Function(object): def init(self, name, argument_types, is_variadic): self.name = name self.argument_types = argument_types self.is_variadic = is_variadic

def __repr__(self):
    return "Function<{}>".format(self.name)

class FunctionLibrary(object): def init(self): pass # TODO

def register(self, list_of_functions):
    pass  # TODO

def find_matches(self, argument_types):
    pass  # TODO

`

I was asked to design a registry system for function overloads (similar to C++/Python dispatch).

• Each function has a name, argument type list, and possibly isVariadic.
• Implement register() to store them.
• Implement find_matches() to return all functions whose argument signatures match (or can match via variadic args).