Climbing stairs stair climb problem, each time can take 1 or 2 steps, climb the n-layer stair total method (disguised fiber nacci)

You are climbing a stair case. It takesNSteps 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?

When n = 1, there is one method, that is, take one step directly.

When n = 2, there are two methods: two steps in a row or two steps in a row.

For N, if F (n) is set to the total method, F (n) = f (n-1) + f (n-2)

PS: F (n-1) is the first step,

F (n-2) is the first two steps

Solution to the back-to-fiber nacci problem:

 1 class Solution { 2 public: 3     int climbStairs(int n) { 4         if(n < 0) 5             return -1; 6         int res[] = {0,1}; 7         if(n<2) 8             return res[n]; 9             10         int fib1 = 0;11         int fib2 = 1;12         13         int result = 1;14         15         for(int i = 1 ; i <= n ; i++){16             result = fib1 + fib2;17             fib1 = fib2;18             fib2 = result;19         }20         21         return result;22     }23 };

 

Climbing stairs stair climb problem, each time can take 1 or 2 steps, climb the n-layer stair total method (disguised fiber nacci)