Abnormal jumping steps

A frog can jump up to 1 steps at a time, or jump up to level 2 ... It can also jump on n levels. To ask the frog to jump on an n-level stair total number of hops

Using FIB (n) to indicate that the frog jumps on the N-Step steps, the frog jumps on the N-Step step number 1 (n-Step) and sets the FIB (0) = 1;

When n = 1 o'clock, there is only one method of jumping, that is, the 1-Step Jump: Fib (1) = 1;

When n = 2 o'clock, there are two ways of jumping, one-step and second-order jumps: fib (2) = FIB (1) + fib (0) = 2;

When n = 3 o'clock, there are three ways to jump, the first step out of one, followed by FIB (3-1) in the Jump method, the first second out of the second, there is a fib (3-2) in the Jump method, after the first jump out of third order, followed by FIB (3-3) in the Jump method

FIB (3) = FIB (2) + fib (1) +fib (0) = 4;

When n = n, there is a total of n jumps, the first step out of one order, followed by FIB (n-1) in the Jump method, after the first second out of the second, there is a fib (n-2) in the Jump method ..... ..... After the first step out of the N-order, there is a Fib (n-n) jump in the back.

FIB (n) = fib (n-1) +fib (n-2) +fib (n-3) +..........+fib (n-n) =fib (0) +fib (1) +fib (2) +.......+fib (n-1)

And because Fib (n-1) =fib (0) +fib (1) +fib (2) +.......+fib (n-2)

Two-type subtraction: FIB (n)-fib (n-1) =fib (n-1) ===== "fib (n) = 2*fib (n-1) n >= 2

public  int Jumpfloorii (int target) {if (target==0) return 1;else if (target==1) return 1;else return 2*jumpfloorii ( target-1);        }

Abnormal jumping steps