剑指offer---跳台阶

public class Solution {
    public int JumpFloor(int target) {
        if(target <= 0){
            return -1;
        } else if(target == 1){
            return 1;
        } else if(target ==2){
            return 2;
        } else{
            return JumpFloor(target -1) + JumpFloor(target - 2);
        }
    }
}