Ways to climb stairs.

ClimbingStairs.cs

public class Solution {
    
    int[] dp;
    public int Climb(int stepsLeft){
        
        if(stepsLeft<0){
            return 0;
        }
        if(stepsLeft==1){
            return 1;
        }
        
        if(stepsLeft==0){
            return 1;
        }
        
        if(dp[stepsLeft]!=0){
            return dp[stepsLeft];
        }
        
        dp[stepsLeft] = Climb(stepsLeft-1) + Climb(stepsLeft-2);

        return dp[stepsLeft];
    }
    public int ClimbStairs(int n) {

        dp = new int[n+1];
        return Climb(n);        
        
    }
}