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Submission #776334

# Submission time Handle Problem Language Result Execution time Memory
776334 2023-07-07T16:58:53 Z I_Love_EliskaM_ Highway Tolls (IOI18_highway) C++14
69 / 100
 195 ms 17784 KB 
#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
#define forn(i,n) for(int i=0;i<n;++i)
#define ll long long
#define pb push_back
#define all(x) x.begin(), x.end()
const ll inf = 1e18;
#define pi pair<int,int>
#define f first
#define s second

const int maxn=2e5;
vector<pi> adj[maxn];
pi e[maxn];
vector<int> z;
void dfs(int u, int p) {
  for(auto&ed:adj[u]) {
    int v=ed.f, i=ed.s;
    if (v==p) continue;
    e[i]={u,v};
    z.pb(i);
    dfs(v,u);
  }
}


mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void find(int n, vector<int>u, vector<int>v, int a, int b) {
  int shift=0;
  while (!((a^b)&1)) {
  	++shift;
  	a>>=1;
  	b>>=1;
  }
  int m=u.size();
  vector<int> f,s;
  ll x;
  forn(it,18) {
    f.clear(), s.clear();
    vector<int> ok(n);
    forn(i,n) ok[i]=rng()&1;
    forn(i,n) (ok[i]?f:s).pb(i);
    if (min(f.size(),s.size())==0) {
      --it; continue;
    }
    vector<int> q(m,0);
    forn(i,m) q[i]=ok[u[i]]==ok[v[i]];
    x = ask(q);
    x>>=shift;
    if (x&1) {
      break;
    }
  }
  if (!(x&1)) exit(0);
  if (f.size()>s.size());
  assert(f.size());
  int l=0, r=f.size()-1;
  while (l<r) {
    int mid=(l+r)>>1;
    vector<int> ok(n);
    for(auto&x:s) ok[x]=1;
    forn(i,mid+1) ok[f[i]]=1;
    vector<int> q(m,0);
    forn(i,m) q[i]=ok[u[i]]==ok[v[i]];
    x = ask(q);
    x>>=shift;
    if (x&1) l=mid+1;
    else r=mid;
  }
  int st = f[r];
  vector<vector<pi>> g(n);
  forn(i,m) {
    g[u[i]].pb({v[i],i});
    g[v[i]].pb({u[i],i});
  }
  vector<int> vis(n); vis[st]=1;
  queue<int> q; q.push(st);
  while (q.size()) {
    auto u=q.front();q.pop();
    for(auto&ed:g[u]) {
      int v=ed.f, i=ed.s;
      if (vis[v]) continue;
      vis[v]=1;
      e[i]={u,v};
      q.push(v);
      z.pb(i);
    }
  }
  l=0, r=n-2;
  ll S=ask(vector<int>(m,1));
  while (l<r) {
    int mid=(l+r)>>1;
    vector<int> q(m,1);
    for(int i=mid+1;i<z.size();++i) q[z[i]]=0;
    ll x=ask(q);
	x>>=shift;
    if (x==S) r=mid;
    else l=mid+1;
  }
  answer(st,e[z[r]].s);

}

void find_pair(int n, vector<int>u, vector<int>v, int a, int b) {
  int m=u.size();
  if (m!=n-1) {
    find(n,u,v,a,b);
    return;
  }
  forn(i,n-1) adj[u[i]].pb({v[i],i}), adj[v[i]].pb({u[i],i});
  int k=0; forn(i,n) if (adj[i].size()==1) k=i;
  dfs(k,-1);

  ll s = ask(vector<int>(m,1));

  int l=0, r=n-2;
  while (l<r) {
    int m=(l+r)>>1;
    vector<int> q(n-1);
    forn(i,m+1) q[z[i]]=1;
    ll x=ask(q);
    if (x==s) r=m;
    else l=m+1;
  }

  k = e[z[r]].s;
  //k=0;
  z.clear();
  dfs(k,-1);

  l=0, r=n-2;
  while (l<r) {
    int m=(l+r)>>1;
    vector<int> q(n-1);
    forn(i,m+1) q[z[i]]=1;
    ll x=ask(q);
    if (x==s) r=m;
    else l=m+1;
  }
  answer(k,e[z[r]].s);

}

Compilation message

highway.cpp: In function 'void find(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:96:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   96 |     for(int i=mid+1;i<z.size();++i) q[z[i]]=0;
      |                     ~^~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4944 KB Output is correct
2 Correct 2 ms 4944 KB Output is correct
3 Correct 3 ms 4952 KB Output is correct
4 Correct 4 ms 4944 KB Output is correct
5 Correct 2 ms 4944 KB Output is correct
6 Correct 2 ms 4944 KB Output is correct
7 Correct 3 ms 4944 KB Output is correct
8 Correct 3 ms 4964 KB Output is correct
9 Correct 2 ms 4944 KB Output is correct
10 Correct 3 ms 4944 KB Output is correct
11 Correct 2 ms 4944 KB Output is correct
12 Correct 3 ms 4944 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5072 KB Output is correct
2 Correct 9 ms 5592 KB Output is correct
3 Correct 123 ms 11332 KB Output is correct
4 Correct 84 ms 11200 KB Output is correct
5 Correct 100 ms 11328 KB Output is correct
6 Correct 111 ms 11324 KB Output is correct
7 Correct 99 ms 11320 KB Output is correct
8 Correct 97 ms 11216 KB Output is correct
9 Correct 125 ms 11328 KB Output is correct
10 Correct 117 ms 11328 KB Output is correct
11 Correct 86 ms 12988 KB Output is correct
12 Correct 107 ms 13628 KB Output is correct
13 Correct 84 ms 13312 KB Output is correct
14 Correct 87 ms 12864 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 6352 KB Output is correct
2 Correct 24 ms 7836 KB Output is correct
3 Correct 29 ms 9192 KB Output is correct
4 Correct 82 ms 17768 KB Output is correct
5 Correct 108 ms 17720 KB Output is correct
6 Correct 64 ms 17720 KB Output is correct
7 Correct 81 ms 17724 KB Output is correct
8 Correct 84 ms 17784 KB Output is correct
9 Correct 115 ms 17784 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5072 KB Output is correct
2 Correct 9 ms 5712 KB Output is correct
3 Correct 71 ms 9908 KB Output is correct
4 Correct 111 ms 11320 KB Output is correct
5 Correct 86 ms 11236 KB Output is correct
6 Correct 89 ms 11324 KB Output is correct
7 Correct 71 ms 11240 KB Output is correct
8 Correct 101 ms 11204 KB Output is correct
9 Correct 102 ms 11260 KB Output is correct
10 Correct 116 ms 11324 KB Output is correct
11 Correct 80 ms 12180 KB Output is correct
12 Correct 91 ms 13332 KB Output is correct
13 Correct 124 ms 12912 KB Output is correct
14 Correct 102 ms 13244 KB Output is correct
15 Correct 90 ms 11316 KB Output is correct
16 Correct 121 ms 11328 KB Output is correct
17 Correct 122 ms 12476 KB Output is correct
18 Correct 110 ms 13068 KB Output is correct
19 Correct 81 ms 11328 KB Output is correct
20 Correct 78 ms 13756 KB Output is correct
21 Correct 64 ms 11512 KB Output is correct
22 Correct 89 ms 11512 KB Output is correct
23 Correct 108 ms 11440 KB Output is correct
24 Correct 71 ms 12204 KB Output is correct
25 Correct 110 ms 17028 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 6096 KB Output is correct
2 Correct 17 ms 6196 KB Output is correct
3 Correct 136 ms 15360 KB Output is correct
4 Correct 104 ms 15928 KB Output is correct
5 Correct 152 ms 17208 KB Output is correct
6 Correct 124 ms 17216 KB Output is correct
7 Correct 133 ms 17176 KB Output is correct
8 Correct 156 ms 17304 KB Output is correct
9 Correct 115 ms 13732 KB Output is correct
10 Correct 132 ms 14268 KB Output is correct
11 Correct 125 ms 15012 KB Output is correct
12 Correct 143 ms 16264 KB Output is correct
13 Correct 128 ms 16840 KB Output is correct
14 Correct 123 ms 17188 KB Output is correct
15 Correct 169 ms 17192 KB Output is correct
16 Correct 145 ms 15020 KB Output is correct
17 Correct 109 ms 15292 KB Output is correct
18 Correct 125 ms 15656 KB Output is correct
19 Correct 98 ms 15444 KB Output is correct
20 Correct 79 ms 15540 KB Output is correct
21 Correct 195 ms 17208 KB Output is correct

Subtask #6
0 / 31.0

# Verdict Execution time Memory Grader output
1 Incorrect 15 ms 6168 KB Output is incorrect: {s, t} is wrong.
2 Halted 0 ms 0 KB -