public class Solution {
public int climbStairs(int n) {
// Start typing your Java solution below
// DO NOT write main() function
// f(n) = f(n-1) + f(n-2);
return fib(n);
}
public int fib(int n){
if(n==1 || n==2)
return n;
else
return fib(n-1) + fib (n-2);
}
}
============================ or
public class Solution {
public int climbStairs(int n) {
// Start typing your Java solution below
// DO NOT write main() function
// f(n) = f(n-1) + f(n-2);
int f0 =1 ,f1 =2;
int result = 0;
for (int i = 0 ; i<n ; i++){
result = f0 + f1;
f0 = f1;
f1= result;
}
return result;
}
}