freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/69bc6cb30c1d112a2e110a09.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
69bc6cb30c1d112a2e110a09	Challenge 252: Unique Stair Climber	29	challenge-252

--description--

Given a number of stairs, return how many distinct ways someone can climb them taking either 1 or 2 steps at a time.

--hints--

get_unique_climbs(4) should return 5.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(4), 5)`)
}})

get_unique_climbs(5) should return 8.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(5), 8)`)
}})

get_unique_climbs(10) should return 89.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(10), 89)`)
}})

get_unique_climbs(18) should return 4181.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(18), 4181)`)
}})

get_unique_climbs(29) should return 832040.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(29), 832040)`)
}})

get_unique_climbs(50) should return 20365011074.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(get_unique_climbs(50), 20365011074)`)
}})

--seed--

--seed-contents--

def get_unique_climbs(steps):

    return steps

--solutions--

def get_unique_climbs(steps):
    if steps <= 0:
        return 0
    if steps == 1:
        return 1
    if steps == 2:
        return 2
    prev2, prev1 = 1, 2
    for _ in range(3, steps + 1):
        prev2, prev1 = prev1, prev2 + prev1
    return prev1