Language: C++

/*
  Verified.
  O(EV log V)
*/
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>

#define INF (1<<29)
#define max_n 10000

using namespace std;

struct edge{int to,cap,rev;};

struct node_t{

  node_t *pp,*lp,*rp;
  int id,val,mini,minId,lazy;
  edge *e;

  node_t(int id,int v):id(id),val(v){
    pp=lp=rp=NULL; lazy=0; update();
  }

  void update(){
    mini=val,minId=id;
    if(lp && mini>lp->mini)mini=lp->mini,minId=lp->minId;
    if(rp && mini>=rp->mini)mini=rp->mini,minId=rp->minId;
  }

  void apply(int v){ lazy+=v, val+=v, mini+=v; }

  void push(){
    if(lp)lp->apply(lazy);
    if(rp)rp->apply(lazy);
    lazy=0;
  }

  bool is_root(){
    return !pp || (pp->lp != this && pp->rp != this);
  }

  void rot(bool isL){
    node_t *q=pp,*r=q->pp;
    q->push(),push();
    if((q->(isL?rp:lp)=(isL?lp:rp)))(isL ? lp : rp)->pp=q;
    (isL ? lp : rp)=q;
    q->pp=this;
    if((pp=r)){
      if(r->lp==q)r->lp=this;
      if(r->rp==q)r->rp=this;
    }
    q->update();
  }

/*
  void rotr(){
    node_t *q=pp,*r=q->pp;
    q->push(),push();
    if((q->lp=rp))rp->pp=q;
    rp=q;q->pp=this;
    if((pp=r)){
      if(r->lp==q)r->lp=this;
      if(r->rp==q)r->rp=this;
    }
    q->update();
  }

  void rotl(){
    node_t *q=pp,*r=q->pp;
    q->push(),push();
    if((q->rp=lp))lp->pp=q;
    lp=q;q->pp=this;
    if((pp=r)){
      if(r->lp==q)r->lp=this;
      if(r->rp==q)r->rp=this;
    }
    q->update();
  }

  void splay(){
    while(!is_root()){
      node_t *q=pp;
      if(q->is_root()){
      	if(q->lp==this)rotr();
      	else rotl();
      } else {
      	node_t *r=q->pp;
      	if(r->lp==q){
      	  if(q->lp==this){q->rotr();rotr();}
      	  else {rotl();rotr();}
      	} else {
      	  if(q->rp==this){q->rotl();rotl();}
      	  else {rotr();rotl();}
      	}
      }
    }
    push();
    update();
  }
  */
  void splay(){
    while(!is_root()){
      node_t *q=pp;
      if(q->is_root()){
        if(q->lp==this)rot(false);
        else rot(true);
      } else {
        node_t *r=q->pp;
        if(r->lp==q){
          if(q->lp==this){q->rot(false);rot(false);}
          else {rot(true);rot(false);}
        } else {
          if(q->rp==this){q->rot(true);rot(true);}
          else {rot(false);rot(true);}
        }
      }
    }
    push();
    update();
  }
};

node_t *expose(node_t *x){
  node_t *rp=NULL;
  for(node_t *p=x;p;p=p->pp){
    p->splay();
    p->rp=rp;
    p->update();
    rp=p;
  }
  x->splay();
  return x;
}

node_t *find_root(node_t *x){
  expose(x);
  while(x->lp)x=x->lp;
  return x;
}

void cut(node_t *c){
  expose(c);
  node_t *p=c->lp;
  c->lp=NULL;
  p->pp=NULL;
  c->val=INF;
}

void link(node_t *c,node_t *p){
  expose(c);
  expose(p);
  c->pp=p;
  p->rp=c;
}

void link(node_t *c,node_t *p,int val,edge *e){
  link(c,p);
  c->val=val;
  c->update();
  c->e=e;
}

int minId(node_t *x){expose(x); return x->minId;}
void add(node_t *x,int val){ expose(x); x->apply(val); }

vector<edge> g[max_n];

void add_edge(int from,int to,int cap){
  g[from].push_back((edge){to,cap,g[to].size()});
  g[to].push_back((edge){from,0,g[from].size()-1});
}

int dist[max_n];

bool bfs(int s,int t){
  fill(dist,dist+max_n,-1);
  dist[s]=0;
  queue<int>que;
  que.push(s);
  while(!que.empty()){
    int u=que.front();que.pop();
    if(u==t)return true;
    for(int j=0;j<g[u].size();j++){
      edge e=g[u][j];
      if(dist[e.to]<0 && e.cap>0){
	dist[e.to]=dist[u]+1;
	que.push(e.to);
      }
    }
  }
  return false;
}

int n,ptr[max_n];
node_t *nodes[max_n];
vector<int>lists[max_n];

bool pour(int id,int i){
  int u=lists[id][i];
  if(find_root(nodes[u])==nodes[u])return true;
  edge *e=nodes[u]->e;
  expose(nodes[u]);
  int df=e->cap-nodes[u]->val;
  e->cap-=df;
  g[e->to][e->rev].cap+=df;
  return false;
}

int max_flow(int S,int T){
  int flow=0;
  while(bfs(S,T)){

    fill(ptr,ptr+max_n,0);
    for(int i=0;i<n;i++)nodes[i]=new node_t(i,INF);

    node_t *s=nodes[S],*t=nodes[T];
    for(int i=0;i<n;i++)lists[i].clear();

    while(true){
      node_t *v=find_root(s);

      if(v==t){
	expose(v=nodes[minId(s)]);
	flow+=v->mini;
	add(s,-v->mini);
	while(true){
	  expose(v=nodes[minId(s)]);
	  if(v->val>0)break;
	  g[v->e->to][v->e->rev].cap+=v->e->cap;
	  v->e->cap=0;
	  cut(v);
	}
	continue;
      }

      if(ptr[v->id] < g[v->id].size()){
	edge &e=g[v->id][ptr[v->id]++];
	if(dist[e.to]==dist[v->id]+1 && e.cap>0){
	  link(v,nodes[e.to],e.cap,&e);
	  lists[e.to].push_back(v->id);
	}
      } else {
	if(v==s){
	  for(int i=0;i<n;i++){
	    for(int j=0;j<lists[i].size();j++)pour(i,j);
	    lists[i].clear();
	  }
	  break;
	}
	for(int i=0;i<lists[v->id].size();i++){
	  if(!pour(v->id,i))cut(nodes[lists[v->id][i]]);
	}
	lists[v->id].clear();
      }
    }
  }
  return flow;
}

// AOJ GRL_6_A
int main(void){

  int e;
  cin >> n >> e;
  for(int i=0;i<e;i++){
    int a,b,c;
    cin >> a >> b >> c;
    add_edge(a,b,c);
  }

  cout << max_flow(0,n-1) << endl;;

  return 0;
}

Compiler output:
a.cc: In member function 'void node_t::rot(bool)':
a.cc:48:12: error: expected unqualified-id before '(' token
   48 |     if((q->(isL?rp:lp)=(isL?lp:rp)))(isL ? lp : rp)->pp=q;
      |            ^
a.cc: In function 'void add_edge(int, int, int)':
a.cc:172:45: warning: narrowing conversion of 'g[to].std::vector<edge>::size()' from 'std::vector<edge>::size_type' {aka 'long unsigned int'} to 'int' [-Wnarrowing]
  172 |   g[from].push_back((edge){to,cap,g[to].size()});
      |                                   ~~~~~~~~~~^~
a.cc:173:47: warning: narrowing conversion of '(g[from].std::vector<edge>::size() - 1)' from 'std::vector<edge>::size_type' {aka 'long unsigned int'} to 'int' [-Wnarrowing]
  173 |   g[to].push_back((edge){from,0,g[from].size()-1});
      |                                 ~~~~~~~~~~~~~~^~