题目通道\]([【XR-4】复读 - 洛谷](https://www.luogu.com.cn/problem/P5597 "【XR-4】复读 - 洛谷"))
```cpp
#include
#define inf 2147483647
using namespace std;
struct ed{
int ls,rs,f,sz,dd;
}p[3000],c[3000];
string s;
int st,lq,ans=inf/2;
int build(int fa,int poi){
p[poi].f=fa; p[poi].sz=1; p[poi].dd=p[fa].dd+1;
if (s[poi]=='3') {
p[poi].ls=build(poi,poi+1), p[poi].sz+=p[p[poi].ls].sz;
p[poi].rs=build(poi,poi+p[poi].sz), p[poi].sz+=p[p[poi].rs].sz;}
if (s[poi]=='2')
p[poi].rs=build(poi,poi+1), p[poi].sz+=p[p[poi].rs].sz;
if (s[poi]=='1')
p[poi].ls=build(poi,poi+1), p[poi].sz+=p[p[poi].ls].sz;
return poi;
}
int gd(int now,string t)
{ int l=t.size();
for (int i=0;i>s; lq=s.size(); s='.'+s;
build(0,1);
search(1,"");
cout<