hello-algo/en/codes/python/chapter_dynamic_programming/climbing_stairs_dp.py
Yudong Jin 1c0f350ad6
translation: Add Python and Java code for EN version (#1345)
* Add the intial translation of code of all the languages

* test

* revert

* Remove

* Add Python and Java code for EN version
2024-05-06 05:21:51 +08:00

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Python

"""
File: climbing_stairs_dp.py
Created Time: 2023-06-30
Author: krahets (krahets@163.com)
"""
def climbing_stairs_dp(n: int) -> int:
"""Climbing stairs: Dynamic programming"""
if n == 1 or n == 2:
return n
# Initialize dp table, used to store subproblem solutions
dp = [0] * (n + 1)
# Initial state: preset the smallest subproblem solution
dp[1], dp[2] = 1, 2
# State transition: gradually solve larger subproblems from smaller ones
for i in range(3, n + 1):
dp[i] = dp[i - 1] + dp[i - 2]
return dp[n]
def climbing_stairs_dp_comp(n: int) -> int:
"""Climbing stairs: Space-optimized dynamic programming"""
if n == 1 or n == 2:
return n
a, b = 1, 2
for _ in range(3, n + 1):
a, b = b, a + b
return b
"""Driver Code"""
if __name__ == "__main__":
n = 9
res = climbing_stairs_dp(n)
print(f"Climb {n} steps, there are {res} solutions in total")
res = climbing_stairs_dp_comp(n)
print(f"Climb {n} steps, there are {res} solutions in total")