LeetCode-in-All
70. Climbing Stairs
Easy
You are climbing a staircase. It takes n steps to reach the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Example 1:
Input: n = 2
Output: 2
Explanation: There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 steps
Example 2:
Input: n = 3
Output: 3
Explanation: There are three ways to climb to the top. 1. 1 step + 1 step + 1 step 2. 1 step + 2 steps 3. 2 steps + 1 step
Constraints:
1 <= n <= 45
Solution
object Solution {
def climbStairs(n: Int): Int = {
if (n < 2) {
return n
}
val cache = new Array[Int](n)
// Initialize the cache for the first two steps
cache(0) = 1
cache(1) = 2
// Fill in the cache using a loop
for (i <- 2 until n) {
cache(i) = cache(i - 1) + cache(i - 2)
}
cache(n - 1)
}
}