已解决。
`if (p->cnt==0||R<=k) return p->cnt;` $\to$ `if (R<=k) return p->cnt;`
by ppip @ 2022-05-26 22:32:18
`if (p->cnt==0||R<=k) return p->cnt;` $\to$ `if (p==nil||R<=k) return p->cnt;`
by ppip @ 2022-05-26 22:32:55