Submission #877286

#	Time	Username	Problem	Language	Result	Execution time	Memory
877286		mgl_diamond	Rigged Roads (NOI19_riggedroads)	C++17	100 / 100	327 ms	72776 KiB

riggedroads

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;
 
#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"

template<class T> bool minimize(T &a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> bool maximize(T &a, T b) { if (a < b) { a = b; return 1; } return 0; }

void setIO() {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  if (fopen(file".inp", "r")) {
    freopen(file".inp", "r", stdin);
    freopen(file".out", "w", stdout);
  }
}

const int N = 3e5+5, LOG = 19;
int n, m, cur, id[N], par[N][LOG], high[N], up_w[N];
vector<ii> edges(1);
vector<ii> adj[N];
bool spec[N];

struct dsu {
  int anc[N], up[N];

  void reset() {
    foru(i, 1, max(n, m)) {
      anc[i] = -1;
      up[i] = i;
    }
  }

  int root(int u) {
    return anc[u] < 0 ? u : anc[u] = root(anc[u]);
  }

  void join(int u, int v) {
    if ((u = root(u)) == (v = root(v))) return;
    if (anc[u] > anc[v]) swap(u, v);
    anc[u] += anc[v];
    if (high[up[u]] > high[up[v]]) up[u] = up[v];
    anc[v] = u;
  }
} comp, proc;

void dfs_first(int u, int p) {
  foru(i, 1, LOG-1) {
    par[u][i] = par[par[u][i-1]][i-1];
  }
  fore(x, adj[u]) {
    int v = x.fi, t = x.se;
    if (v == p) continue;
    up_w[v] = t;
    high[v] = high[u] + 1;
    par[v][0] = u;
    dfs_first(v, u);
  }
}

int lca(int u, int v) {
  if (high[u] < high[v]) swap(u, v);
  ford(i, LOG-1, 0) if (high[par[u][i]] >= high[v]) u = par[u][i];
  if (u == v) return u;
  ford(i, LOG-1, 0) if (par[u][i] != par[v][i]) {
    u = par[u][i];
    v = par[v][i];
  }
  return par[u][0];
}

int main() {
  setIO();

  cin >> n >> m;
  foru(i, 1, m) {
    int u, v;
    cin >> u >> v;
    edges.emplace_back(u, v);
  }

  foru(i, 1, n-1) {
    int e; cin >> e;
    spec[e] = 1;
    int u = edges[e].fi, v = edges[e].se;
    adj[u].emplace_back(v, e);
    adj[v].emplace_back(u, e);
  }

  high[0] = -1;
  dfs_first(1, 0);

  comp.reset();
  proc.reset();
  foru(i, 1, m) {
    if (id[i]) continue;
    int u = edges[i].fi, v = edges[i].se;
    if (!spec[i]) {
      int l = lca(u, v);
      vector<int> tmp;
      u = proc.up[proc.root(u)];
      v = proc.up[proc.root(v)];
      while (high[u] > high[l]) {
        if (!id[up_w[u]]) tmp.push_back(up_w[u]);
        proc.join(u, par[u][0]);
        u = proc.up[proc.root(u)];
      }
      while (high[v] > high[l]) {
        if (!id[up_w[v]]) tmp.push_back(up_w[v]);
        proc.join(v, par[v][0]);
        v = proc.up[proc.root(v)];
      }
      sort(all(tmp));
      // fore(x, tmp) {
      //   cout << x << " ";
      // }
      // cout << "\n";
      fore(x, tmp) {
        id[x] = ++cur;
      }
    }
    id[i] = ++cur;
  }
  foru(i, 1, m) cout << id[i] << " ";
}

Compilation message (stderr)

riggedroads.cpp: In function 'void setIO()':
riggedroads.cpp:22:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |     freopen(file".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
riggedroads.cpp:23:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |     freopen(file".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 19 / 19
• Subtask 3: 9 / 9
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 12 / 12
• Subtask 7: 32 / 32