Submission #303120

#	Time	Username	Problem	Language	Result	Execution time	Memory
303120		VROOM_VARUN	Connecting Supertrees (IOI20_supertrees)	C++14	11 / 100	250 ms	26104 KiB

supertrees

/*
ID: varunra2
LANG: C++
TASK: supertrees
*/

#include <bits/stdc++.h>
using namespace std;
#include "supertrees.h"

#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
  cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif

#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e9
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second

const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions

int n;
VVI p;
VVI ret;

bool isBad() {
  for (int i = 0; i < n; i++) {
    if (p[i][i] != 1) return false;
  }

  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      if (p[i][j] != p[j][i]) return false;
    }
  }

  return true;
  // change/update later
}

void dfs(int i, vector<bool>& vis, int bnd, VI& cmp) {
  if (vis[i]) return;
  vis[i] = true;
  cmp.PB(i);
  for (int ii = 0; ii < n; ii++) {
    if (i == ii) continue;
    if (p[i][ii] >= bnd) {
      dfs(ii, vis, bnd, cmp);
    }
  }
}

// void solve(VI& comp) {

// }

struct dsu {
  VI par;
  VI siz;
  int n;
  void init(int _n) {
    n = _n;
    par.resize(n);
    siz.resize(n);
    for (int i = 0; i < n; i++) {
      par[i] = i;
      siz[i] = 1;
    }
  }

  bool ispar(int x) { return x == par[x]; }

  int find(int x) {
    while (par[x] != par[par[x]]) par[x] = par[par[x]];
    return par[x];
  }

  bool same(int x, int y) { return find(x) == find(y); }

  void merge(int x, int y) {
    x = find(x);
    y = find(y);
    if (siz[x] < siz[y]) swap(x, y);
    par[y] = x;
    siz[x] += siz[y];
  }
};

void edge(int u, int v) {
  // make an edge between u and v
  if (u < 0 or v < 0 or u >= n or v >= n) return;

  ret[u][v] = 1;
  ret[v][u] = 1;
}

int buildcycle(VI& comp) {
  // build a cycle, first element is the parent
  if (sz(comp) == 1) return 1;
  if(sz(comp) == 2) return 0;
  edge(comp[0], comp.back());
  for (int i = 0; i < sz(comp) - 1; i++) {
    edge(comp[i], comp[i + 1]);
  }
  return 1;
}

void buildtree(VI& comp) {
  // build tree, first element is root
  for (int i = 1; i < sz(comp); i++) {
    edge(comp[0], comp[i]);
  }
}

// void build(VVI& a) {
//   // bruh
//   // debug(a);
//   debug("here");
//   for (int i = 0; i < n; i++) {
//     debug(i, a[i]);
//   }
// }

int construct(VVI asdf) {
  n = sz(asdf);
  p = asdf;

  ret.resize(n);

  trav(x, asdf) trav(y, x) if (y == 3) return 0;

  for (int i = 0; i < n; i++) {
    ret[i].resize(n);
  }

  // vector<bool> vis(n, false);

  // for(int i = 0; i < n; i++) {
  // if(vis[i]) continue;
  // VI comp;
  // dfs(i, vis, 1, comp);
  // solve(comp);
  // }

  // merge all 2's together
  //

  dsu g1, g2;

  g1.init(n);
  g2.init(n);

  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (p[i][j] >= 1)
        if (!g1.same(i, j)) g1.merge(i, j);
      if (p[i][j] >= 2)
        if (!g2.same(i, j)) g2.merge(i, j);
    }
  }

  // if we need to connect 2 nodes, we do it through their parent in dsu2

  for (int i = 0; i < n; i++) {
    if (g2.ispar(i)) {
      VI comp;
      comp.PB(i);
      for (int j = 0; j < n; j++) {
        if (g2.find(j) == i and j != i) {
          comp.PB(j);
        }
      }
      int res = buildcycle(comp);
      if(!res) return 0;
    }
  }

  for (int i = 0; i < n; i++) {
    if (g1.ispar(i)) {
      VI comp;
      comp.PB(i);
      for (int j = 0; j < n; j++) {
        if (g2.ispar(j) and g1.find(j) == i and j != i) {
          comp.PB(j);
        }
      }
      buildtree(comp);
    }
  }

  build(ret);
  return 1;
}

// int main() {
// #ifndef ONLINE_JUDGE
//   freopen("supertrees.in", "r", stdin);
//   freopen("supertrees.out", "w", stdout);
// #endif
//   cin.sync_with_stdio(0);
//   cin.tie(0);

//   int n;
//   cin >> n;

//   VVI vals(n, VI(n));

//   for (int i = 0; i < n; i++) {
//     for (int j = 0; j < n; j++) {
//       cin >> vals[i][j];
//     }
//   }

//   int x = construct(vals);

//   debug(x);

//   return 0;
// }

• Subtask 1: 11 / 11
• Subtask 2: 0 / 10
• Subtask 3: 0 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4