Submission #237818

#	Time	Username	Problem	Language	Result	Execution time	Memory
237818		Nucleist	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	814 ms	83940 KiB

oneway

#include <bits/stdc++.h> 
using namespace std; 
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#define flash ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define debug(x) cerr << " - " << #x << ": " << x << endl;
#define debugs(x, y) cerr << " - " << #x << ": " << x << " " << #y << ": " << y << endl;
#define all(x) (x).begin(),(x).end()
#define sz(x) (ll)x.size()
#define ll long long
#define INF 1000000000
#define MOD 1000000007
#define pb push_back
#define ve vector<ll>
#define dos pair<ll,ll>
#define vedos vector<dos>
#define rand mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define EPS 0.000001
struct greateri
{
    template<class T>
    bool operator()(T const &a, T const &b) const { return a > b; }
};
void setIO(string s) {
  ios_base::sync_with_stdio(0); cin.tie(0); 
  freopen((s+".in").c_str(),"r",stdin);
  freopen((s+".out").c_str(),"w",stdout);
}
ll tin[200001],tlow[200001],vis[200001],vis1[200001],dep[200001],pa[200001][30];
ve gr[200001],gr1[200001],tr[200001];
set<dos>brid;
ll n,m,p;
char ans[200001];
map<dos,ve>g;
ll timer,l;
ll col[200001];
void dfs(ll node,ll p){
  vis[node]=1;
  tin[node]=timer++;
  tlow[node]=tin[node];
  for(auto it:gr[node]){
    if(it==p || it==node)continue;
    if(vis[it]){
      tlow[node]=min(tin[it],tlow[node]);
    }
    else{
      dfs(it,node);
      tlow[node]=min(tlow[node],tlow[it]);
      if(tlow[it]>tin[node]){
        brid.insert({min(node,it),max(node,it)});
      }
    }
  }
}
void dfs1(ll node,ll co){
  col[node]=co;
  vis1[node]=1;
  for(auto it:gr1[node]){
    if(!vis1[it]){
      dfs1(it,co);
    }
  }
}
void dfk(ll node,ll p,ll ka){
  vis1[node]=1;
  tin[node]=timer++;
  dep[node]=ka;
  pa[node][0]=p;
  for (ll i = 1; i <= l; ++i)
  {
    pa[node][i]=pa[pa[node][i-1]][i-1];
  }
  for(auto it:tr[node]){
    if(it!=p){
      dfk(it,node,ka+1);
    }
  }
  tlow[node]=timer++;
}
bool is_anc(ll u,ll v){
  if(tin[u]<=tin[v] && tlow[u]>=tlow[v])return 1;
  return 0;
}
ll lca(ll u,ll v){
  if(is_anc(u,v))return u;
  if(is_anc(v,u))return v;
  for (ll i = l; i >= 0; --i)
  {
    if(!is_anc(pa[u][i],v)){
      u=pa[u][i];
    }
  }
  return pa[u][0];
}
ll parent[200000], depth[200000], heavy[200000], head[200000], pos[200000];
ll cur_pos;
ll lom(ll v) {
    vis1[v]=1;
    ll size = 1;
    ll max_c_size = 0;
    for (ll c : tr[v]) {
        if (c != parent[v]) {
            parent[c] = v, depth[c] = depth[v] + 1;
            ll c_size = lom(c);
            size += c_size;
            if (c_size > max_c_size)
                max_c_size = c_size, heavy[v] = c;
        }
    }
    return size;
}

ll decompose(ll v, ll h) {
    head[v] = h, pos[v] = cur_pos++;
    if (heavy[v] != -1)
      decompose(heavy[v], h);
    for (ll c : tr[v]) {
        if (c != parent[v] && c != heavy[v])
          decompose(c, c);
    }
}
ll bit[200001];
void add(ll idx, ll val) {
    for (idx; idx <= n; idx += idx & -idx)
        bit[idx] += val;
}

void range_add(ll l, ll r, ll val) {
    add(l, val);
    add(r + 1, -val);
}

ll point_query(ll idx) {
    ll ret = 0;
    for (idx; idx > 0; idx -= idx & -idx)
        ret += bit[idx];
    return ret;
}
void query(ll a, ll b,ll val) {
    ll res = 0;
    for (; head[a] != head[b]; b = parent[head[b]]) {
        if (depth[head[a]] > depth[head[b]])
            swap(a, b);
        //debugs(pos[head[b]],pos[b])
        //debug(val)
        range_add(pos[head[b]]+1, pos[b]+1,val);
        //debug(point_query(pos[head[b]]+1))
        //res = max(res, cur_heavy_path_max);
    }
    if (depth[a] > depth[b])
      swap(a, b);
    //debugs(a,b)
    //debug(val)
    range_add(pos[a]+1, pos[b]+1,val);
    return;
}
int main()
{
  //flash;
  cin>>n>>m;
  l=log2(n);
  vedos ed;
  for (ll i = 0; i < m; ++i)
  {
    ll u,v;
    cin>>u>>v;
    u--,v--;
    if(u==v){
      ans[i]='B';
    }
    else{
      ed.pb({u,v});
      gr[u].pb(v),gr[v].pb(u);
      if(u>v)swap(u,v);
      g[{u,v}].pb(i);
    }   
  }
  for(auto it:g){
    if(it.second.size()>1){
      for(auto it1:it.second){
        ans[it1]='B';
      }
    }
  }
  for (int i = 0; i < n; ++i)
  {
    if(!vis[i])dfs(i,-1);
  }
  set<dos>rem;
  for(auto it:brid){
    if(g[{it.first,it.second}].size()>1)rem.insert(it);
  }
  for(auto it:rem)brid.erase(it);
  for(auto it:ed){
    auto u=it.first,v=it.second;
    if(u>v)swap(u,v);
    if(brid.find({u,v})==brid.end()){
      gr1[u].pb(v),gr1[v].pb(u);
    }
  }
  ll ci=1;
  for (ll i = 0; i < n; ++i)
  {
    if(!vis1[i]){
      dfs1(i,ci);
      ci++;
    }
  }
  timer=0;
  for(auto it:brid){
    tr[col[it.first]].pb(col[it.second]);
    tr[col[it.second]].pb(col[it.first]);
  }
  memset(vis1,0,sizeof vis1);
  for (int i = 1; i < ci; ++i)
  {
    if(!vis1[i]){timer=0,dfk(i,i,0);}
  }
  ll q;
  cin>>q;
  memset(heavy,-1,sizeof heavy);   
  memset(vis1,0,sizeof vis1);  
  for (int i = 1; i < ci; ++i)
  {
    if(!vis1[i]){lom(i),decompose(i,i);}
  }
  while(q--){
    ll u,v;
    cin>>u>>v;
    u--,v--;
    if(col[u]==col[v])continue;
    ll dol=lca(col[u],col[v]);
    query(col[u],dol,1);
    query(col[v],dol,-1);
  }
  for (ll i = 0; i < ed.size(); ++i)
  {
    auto u=ed[i].first,v=ed[i].second;
    if(u>v)swap(u,v);
    if(ans[i]!='B' && brid.find({u,v})!=brid.end() && col[u]!=col[v]){
      if(dep[col[u]]<=dep[col[v]])swap(u,v);
      ll cur=point_query(pos[col[u]]+1);
      if(cur>0){
        if(ed[i].first==u)ans[i]='R';
        else ans[i]='L';
      } 
      else if(cur<0){
        if(ed[i].first==u)ans[i]='L';
        else ans[i]='R';
      }
      else ans[i]='B';
    }
    else ans[i]='B';
  }
  for (ll i = 0; i < m; ++i)
  {
    cout<<ans[i];
  }
  return 0;
}
//code the AC sol !
// BS/queue/map

Compilation message (stderr)

oneway.cpp:4:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
oneway.cpp:5:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")
 
oneway.cpp: In function 'long long int decompose(long long int, long long int)':
oneway.cpp:122:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
oneway.cpp: In function 'void add(long long int, long long int)':
oneway.cpp:125:13: warning: statement has no effect [-Wunused-value]
     for (idx; idx <= n; idx += idx & -idx)
             ^
oneway.cpp: In function 'long long int point_query(long long int)':
oneway.cpp:136:13: warning: statement has no effect [-Wunused-value]
     for (idx; idx > 0; idx -= idx & -idx)
             ^
oneway.cpp: In function 'void query(long long int, long long int, long long int)':
oneway.cpp:141:8: warning: unused variable 'res' [-Wunused-variable]
     ll res = 0;
        ^~~
oneway.cpp: In function 'int main()':
oneway.cpp:237:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (ll i = 0; i < ed.size(); ++i)
                  ~~^~~~~~~~~~~
oneway.cpp: In function 'void setIO(std::__cxx11::string)':
oneway.cpp:27:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen((s+".in").c_str(),"r",stdin);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:28:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen((s+".out").c_str(),"w",stdout);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40