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 step + 1 step
-
2 steps
Example 2:
Input: n = 3
Output: 3
Explanation: There are three ways to climb to the top.
-
1 step + 1 step + 1 step
-
1 step + 2 steps
-
2 steps + 1 step
Constraints:
1 <= n <= 45
Solution
func climbStairs(n int) int {
f := make([]int, n+1)
f[0] = 1
f[1] = 2
if n > 2 {
for i := 2; i < n; i++ {
f[i] = f[i-1] + f[i-2]
}
}
return f[n-1]
}