//常规思路,关键要找到公式code
public class Solution {get
public int JumpFloorII(int target) { if(target==1||target==2) return target; int f2=2,i=3,fn=0; while(i<=target){ fn=2*f2; f2=fn; i++; } return fn; }
}io
//牛客网好的思路,采用左移的思路,真的简洁,代码看起来好爽 public class Solution { public int JumpFloorII(int target) { return 1<<(target-1); } }class