Submission #330855

#	Time	Username	Problem	Language	Result	Execution time	Memory
330855		VROOM_VARUN	Election Campaign (JOI15_election_campaign)	C++14	100 / 100	335 ms	46700 KiB

election_campaign

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

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

#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

struct LCA {
  VVI adj;
  VVI st;
  int n;
  VI tin;
  VI tout;
  int t = 0;
  const int bits = 20;

  void dfs(int u, int v) {
    st[u][0] = v;
    for (int i = 1; i < bits; i++) {
      int to = st[u][i - 1];
      if (to == -1)
        st[u][i] = -1;
      else
        st[u][i] = st[to][i - 1];
    }
    tin[u] = t++;
    for (auto& x : adj[u]) {
      if (x == v) continue;
      dfs(x, u);
    }
    tout[u] = t++;
  }

  void init(VVI& _adj) {
    adj = _adj;
    n = sz(adj);
    tin.resize(n);
    tout.resize(n);
    st.resize(n);
    trav(x, st) x.resize(bits);
    dfs(0, -1);
  }

  bool isAnc(int u, int v) {
    if (u == -1) return true;
    if (v == -1) return false;
    return tin[u] <= tin[v] and tout[u] >= tout[v];
  }

  int getLCA(int u, int v) {
    if (isAnc(u, v)) return u;
    if (isAnc(v, u)) return v;

    for (int i = bits - 1; ~i; i--) {
      if (!isAnc(st[u][i], v)) u = st[u][i];
    }

    return st[u][0];
  }
} lca;

struct BIT {
  // range update, point query
  VI fen;
  int n;

  void init(int _n) {
    n = _n;
    fen.resize(n + 1);
  }

  void upd(int ind, int val) {
    ind++;
    while (ind <= n) {
      fen[ind] += val;
      ind += (ind & -ind);
    }
  }

  void upd(int l, int r, int val) {
    upd(l, val);
    upd(r + 1, -val);
  }

  int qry(int ind) {
    int ret = 0;
    ind++;
    while (ind >= 1) {
      ret += fen[ind];
      ind -= (ind & -ind);
    }
    return ret;
  }
};

VVI adj;
VVI events;
VI ord;
VVI qrys;
VI pos;
VI dp;
VI par;
VI lran, rran;
int n, m;

void init() {
  events.resize(n);
  qrys.resize(m);
  pos.resize(n);
  lran.resize(n);
  rran.resize(n);
  par.resize(n);
  dp.resize(n);
}

void dfsord(int u, int v) {
  pos[u] = sz(ord);
  lran[u] = sz(ord);
  par[u] = v;
  ord.PB(u);
  trav(x, adj[u]) {
    if (x == v) continue;
    dfsord(x, u);
  }
  rran[u] = sz(ord) - 1;
}

BIT chldval, dpval;

void dpdfs(int u, int v) {
  int chldsum = 0;
  trav(x, adj[u]) {
    if (x == v) continue;
    dpdfs(x, u);
    chldsum += dp[x];
  }

  dp[u] = chldsum;

  trav(x, events[u]) {
    int uu, vv, c;
    uu = qrys[x][0], vv = qrys[x][1], c = qrys[x][2];
    int sum = 0;
    c += chldval.qry(pos[uu]);
    c += chldval.qry(pos[vv]);
    c -= dpval.qry(pos[uu]);
    c -= dpval.qry(pos[vv]);
    c += chldsum;
    dp[u] = max(dp[u], c);
  }

  chldval.upd(lran[u], rran[u], chldsum);
  dpval.upd(lran[u], rran[u], dp[u]);
}

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

  cin >> n;

  adj.resize(n);

  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    adj[u].PB(v);
    adj[v].PB(u);
  }

  cin >> m;

  init();

  lca.init(adj);

  for (int i = 0; i < m; i++) {
    qrys[i].resize(3);
    cin >> qrys[i][0] >> qrys[i][1] >> qrys[i][2];
    qrys[i][0]--, qrys[i][1]--;
    int lc = lca.getLCA(qrys[i][0], qrys[i][1]);
    events[lc].PB(i);
  }

  dfsord(0, -1);

  chldval.init(n);

  dpval.init(n);

  dpdfs(0, -1);

  cout << dp[0] << '\n';

  return 0;
}

Compilation message (stderr)

election_campaign.cpp: In function 'void dpdfs(int, int)':
election_campaign.cpp:190:9: warning: unused variable 'sum' [-Wunused-variable]
  190 |     int sum = 0;
      |         ^~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40