Submission #486411

#	Time	Username	Problem	Language	Result	Execution time	Memory
486411		BERNARB01	Graph (BOI20_graph)	C++17	5 / 100	11 ms	19200 KiB

Graph

#include <bits/stdc++.h>

using namespace std;

using ld = long double;

class dsu {
  public:
  vector<int> p, h;
  int n, nCC;

  dsu() {}

  dsu(int _n) : n(_n), nCC(n) {
    p.resize(n);
    iota(p.begin(), p.end(), 0);
    h.assign(n, 0);
  }

  void init(int _n) {
    n = _n;
    nCC = n;
    p.resize(n);
    iota(p.begin(), p.end(), 0);
    h.assign(n, 0);
  }

  inline int get(int x) {
    return (x == p[x] ? x : (p[x] = get(p[x])));
  }

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

  inline bool unite(int x, int y) {
    x = get(x);
    y = get(y);
    if (x == y) {
      return false;
    }
    --nCC;
    if (h[x] > h[y]) {
      swap(x, y);
    }
    p[x] = y;
    h[y] += (h[x] == h[y]);
    return true;
  }
};

const int N = (int) 2e5 + 9;
const ld inf = (ld) 1e7 + 9;
ld vals[] = {-2, -1.5, -1, -.5, 0, .5, 1, 1.5, 2};

int n, m, vis[N];
ld a[N], finalV[N], S[N];
map<int, ld> W[N];
vector<pair<int, ld>> g[N];
vector<int> comps[N];

ld dfs(int v) {
  vis[v] = 1;
  ld ret = fabsl(a[v]);
  for (auto [u, w] : g[v]) {
    if (vis[u]) {
      if (a[u] + a[v] != w) {
        return inf;
      }
      continue;
    }
    a[u] = w - a[v];
    ret += dfs(u);
    if (ret >= inf) {
      return inf;
    }
  }
  return ret;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m;
  fill(S, S + n, -1);
  dsu se(n);
  set<pair<int, int>> see;
  for (int i = 0; i < m; i++) {
    int u, v;
    ld w;
    cin >> u >> v >> w;
    --u; --v;
    if (u == v && S[v] != -1) {
      if (S[v] != w) {
        cout << "NO" << '\n';
        return 0;
      }
    }
    if (u == v) {
      S[v] = w;
    }
    if (see.count({u, v})) {
      if (W[u][v] != w) {
        cout << "NO" << '\n';
        return 0;
      }
    } else {
      g[u].emplace_back(v, w);
      g[v].emplace_back(u, w);
    }
    W[u][v] = w;
    W[v][u] = w;
    see.insert({u, v});
    see.insert({v, u});
    se.unite(u, v);
  }
  for (int i = 0; i < n; i++) {
    comps[se.get(i)].push_back(i);
  }
  for (int i = 0; i < n; i++) {
    if (comps[i].empty() || vis[i]) {
      continue;
    }
    int start = comps[i][0];
    ld ans = -1;
    for (ld x : vals) {
      a[start] = x;
      for (int u : comps[i]) {
        vis[u] = 0;
      }
      ld z = dfs(start);
      if (z < inf && (ans == -1 || z < ans)) {
        ans = z;
        for (int u : comps[i]) {
          finalV[u] = a[u];
        }
      }
    }
    if (ans == -1) {
      cout << "NO" << '\n';
      return 0;
    }
  }
  cout << "YES" << '\n';
  for (int i = 0; i < n; i++) {
    if (i > 0) {
      cout << " ";
    }
    cout << finalV[i];
  }
  cout << '\n';
  return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 12
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 42