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?
1 class Solution { 2 public: 3 int climbStairs(int n) { 4 if(n==0) 5 return 0; 6 else if(n==1) 7 return 1; 8 else if(n==2) 9 return 2; 10 else 11 return climbStairs(n-1)+climbStairs(n-2); 12 } 13 };
1 class Solution { 2 public: 3 int climbStairs(int n) { 4 if(n==0) 5 return 0; 6 int a[n+1]; 7 a[0]=1; 8 a[1]=1; 9 for(int i=2;i<=n;i++) 10 a[i]=a[i-1]+a[i-2]; 11 return a[n]; 12 } 13 };