Description
You are climbing a stair case. It takes n steps to reach to the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Note: Given n will be a positive integer.
Examples
Example 1:
Input: 2
Output: 2
Explanation: There are two ways to climb to the top.
- 1 step + 1 step
- 2 steps
Example 2:
Input: 3
Output: 3
Explanation: There are three ways to climb to the top.
4. 1 step + 1 step + 1 step
5. 1 step + 2 steps
6. 2 steps + 1 step
Solution(C++)
class Solution {
public:
int climbStairs(int n) {
if(n==1) return 1;
if(n==2) return 2;
int *p = new int[n];
p[0] = 1;
p[1] = 2;
for (int i = 2; i < n; i++) {
p[i] = p[i - 1] + p[i - 2];
}
return p[n - 1];
}
};