是 MLE
by 蒟酱 @ 2022-11-14 16:05:50
可以确定不是 `vector` 存边的问题：
```cpp
//不向焦虑与抑郁投降，这个世界终会有我们存在的地方。
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cassert>
#include<tuple>
#include<ctime>
#include<random>
#if __cplusplus>=202002L
#include<ranges>
namespace vw=std::views;
#endif
#define siz(x) int((x).size())
#define cauto const auto
#define all(x) std::begin(x),std::end(x)
#define rall(x) std::rbegin(x),std::rend(x)
#define sqrt __builtin_sqrt
#define fi first
#define se second
#define continue(x) {x;continue;}
#define break(x) {x;break;}
using std::cin;using std::cout;
using std::max;using std::min;
using std::tie;using std::ignore;
template<typename any>inline void cmin(any &x,const any &y){if(y<x)x=y;}
template<typename any>inline void cmax(any &x,const any &y){if(x<y)x=y;}
template<typename any,typename...args>inline void cmax(any &x,const any &y,const args &...z){cmax(x,y);cmax(x,z...);}
template<typename any,typename...args>inline void cmin(any &x,const any &y,const args &...z){cmin(x,y);cmin(x,z...);}
using loli=long long;
using uloli=unsigned long long;
using lodb=long double;
using venti=__int128_t;
using pii=std::pair<int,int>;
using tiii=std::tuple<int,int,int>;
using inlsi=const std::initializer_list<int>&;
using bsi=std::basic_string<int>;
using bsc=std::string;
using std::operator""s;
#if __cplusplus>=201703L
using bscv=std::string_view;
using std::operator""sv;
#endif
struct _time{~_time(){std::cerr<<"\n\033[33;40m"<<1.*clock()/CLOCKS_PER_SEC<<"s\033[37;40m";}}_TM;
std::mt19937 rng(std::random_device{}());
constexpr venti operator""_vt(uloli x){return venti(x);}
constexpr bool ying=false,yang=true;
constexpr int N=1e5+1,M=2e6+1;
int n,m,deg[N];
bool vis[N],ins[N],del[M];
bsi s,e,g[N];
bsi::iterator hed[N];
std::vector<bsi>ans;
int l=1,nxt[M],head[M],go[M];
void add(int u,int v){nxt[++l]=head[u],head[u]=l,go[l]=v;}
void dfs(int u){
vis[u]=true;
// for(auto it=hed[u];it!=g[u].end();++it)if(int v=e[*it];!del[*it]){
for(int j=head[u],v=go[j];j;j=nxt[j],v=go[j]){
// del[*it]=del[*it^1]=yang;
// hed[u]=next(it);
del[j]=del[j^1]=yang;
head[u]=nxt[j];
dfs(v);
if(ins[v]){
ans.emplace_back(v,1);
for(;s.back()!=v;s.pop_back())
ans.back()+=s.back(),ins[s.back()]=ying;
}else s+=v,ins[v]=yang;
}
}
signed main(){
// freopen(".in","r",stdin);
// freopen(".out","w",stdout);
std::ios::sync_with_stdio(false);cin.tie(nullptr);
cin>>n>>m;
for(int i=1,u,v,c1,c2;i<=m;i++){
cin>>u>>v>>c1>>c2;
if(c1!=c2)
// g[u]+=siz(e),e+=v,
// g[v]+=siz(e),e+=u,
add(u,v),add(v,u),
deg[u]++,deg[v]++;
}
for(int i=1;i<=n;i++)if(deg[i]&1)return cout<<"NIE",0;
for(int i=1;i<=n;i++)hed[i]=g[i].begin();
for(int i=1;i<=n;i++)if(!vis[i]){
dfs(i);
if(ins[i]){
for(int j:s)ins[j]=ying;
ans.emplace_back().swap(s);
}
}
cout<<siz(ans)<<'\n';
for(cauto&v:ans){
cout<<siz(v)<<' ';
for(int i:v)cout<<i<<' ';
cout<<v.front()<<'\n';
}
return 0;
}
```
by 蒟酱 @ 2022-11-14 16:28:08
已经解决，`basic_string` 的构造函数调用错误。
```cpp
ans.emplace_back(1,v);
```
by 蒟酱 @ 2022-11-14 16:35:04