“狡兔三窟”是说兔子有很多可以躲藏的洞穴来保护自己的安全，现在有一只狐狸，一只兔子，还有兔子的10个洞（洞口编号0~9）。

狐狸是这样找兔子的，首先：狐狸站在0号洞口，步长是1（此时步长为1），则下一个洞口是1号洞，站在1号洞口，步长+1（此时步长为2），则下一个洞口是3号洞，站在3号洞口，步长+1（此时步长为3），则下一个洞口是6号洞...等等

问：狐狸能不能抓到兔子，请写代码证明。-The "Jiaotusanku" means many rabbits can hide the cave to protect themselves, now let s hypothesis that there have a fox, a rabbit and 10 holes (hole numbers 0 to 9) for rabbits.

Fox so find rabbit, First hole: fox standing No. 0, step 1 (step 1), the next hole is on the 1st hole, standing on the 1st hole, step+1 (this 2) time step, the next hole is on the 3rd hole, standing on the 3rd hole, step+1 (step 3), the next hole is on the 6th hole ... etc.

Q: fox can catch the rabbit, please write code to prove.