Climbing Stairs
Problem Statement - link #
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?
Examples #
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 #
class Solution {
public:
int climbStairs(int n) {
int dp[n+1];
dp[0] = 1;
for(int i=1; i<n+1; i++){
int waystoi = 0;
if(i-2 >= 0)
waystoi = dp[i-2];
waystoi += dp[i-1];
dp[i] = waystoi;
}
return dp[n];
}
};