Learner Level
Implement the climbStairsWays method that returns the number of distinct ways to climb n stairs.
The input contains an integer n, representing the number of stairs. You can climb either 1 stair or 2 stairs at a time.
Your task is to return how many distinct ways you can reach the top. For example, when n = 3, the possible ways are 1+1+1, 1+2, and 2+1, so the answer is 3.
Example 1
Input
n (int) =
2Returns (int)
2Example 2
Input
n (int) =
3Returns (int)
3Example 3
Input
n (int) =
5Returns (int)
8To reach stair n, the last move must come from stair n - 1 using one step, or from stair n - 2 using two steps.
So the number of ways to reach stair n is the sum of ways to reach n - 1 and n - 2. This is similar to the Fibonacci sequence.
Pseudocode:
function climbStairsWays(n):
if n <= 1:
return 1
prev2 = 1
prev1 = 1
for stair from 2 to n:
current = prev1 + prev2
prev2 = prev1
prev1 = current
return prev1Ready to test your solutionRun Code checks your solution against the test cases.Shift + Enter to run