Submission #528614

#	Time	Username	Problem	Language	Result	Execution time	Memory
528614		Alex_tz307	Election Campaign (JOI15_election_campaign)	C++17	10 / 100	135 ms	30132 KiB

election_campaign

#include <bits/stdc++.h>

using namespace std;

const int kN = 1e5;
const int kLog = 16;
int n, timer, tin[1 + kN], tout[1 + kN], depth[1 + kN], anc[1 + kN][1 + kLog];
vector<int> g[1 + kN];
vector<tuple<int, int, int>> paths[1 + kN];
int64_t ans, aib[1 + kN], sum[1 + kN];

void maxSelf(int64_t &x, int64_t y) {
  if (x < y) {
    x = y;
  }
}

void update(int64_t aib[], int x, int v) {
  for (int i = x; i <= n; i += i & -i) {
    aib[i] += v;
  }
}

int64_t query(int64_t aib[], int x) {
  int64_t ans = 0;
  for (int i = x; i > 0; i = i & (i - 1)) {
    ans += aib[i];
  }
  return ans;
}

int64_t query(int64_t aib[], int l, int r) {
  return query(aib, r) - query(aib, l);
}

void dfs1(int u) {
  tin[u] = ++timer;
  for (int i = 1; i <= kLog; ++i) {
    anc[u][i] = anc[anc[u][i - 1]][i - 1];
    if (anc[u][i] == 0) {
      break;
    }
  }
  for (int v : g[u]) {
    if (v != anc[u][0]) {
      anc[v][0] = u;
      depth[v] = depth[u] + 1;
      dfs1(v);
    }
  }
  tout[u] = timer;
}

int getLca(int u, int v) {
  if (depth[u] < depth[v]) {
    swap(u, v);
  }
  for (int i = kLog; i >= 0; --i) {
    if (depth[u] - (1 << i) >= depth[v]) {
      u = anc[u][i];
    }
  }
  if (u == v) {
    return u;
  }
  for (int i = kLog; i >= 0; --i) {
    if (anc[u][i] != anc[v][i]) {
      u = anc[u][i];
      v = anc[v][i];
    }
  }
  return anc[u][0];
}

int64_t dfs2(int u) {
  int64_t sumChildren = 0, dp = 0;
  for (int v : g[u]) {
    if (v != anc[u][0]) {
      int64_t ret = dfs2(v);
      maxSelf(dp, ret);
      sumChildren += ret;
    }
  }
  update(sum, tin[u], sumChildren);
  update(sum, tout[u] + 1, -sumChildren);
  for (auto it : paths[u]) {
    int p, q, w;
    tie(p, q, w) = it;
    maxSelf(dp, query(sum, tin[u], tin[p]) + query(sum, tin[u], tin[q]) + sumChildren + w
                - query(aib, tin[u], tin[p]) - query(aib, tin[u], tin[q]));
  }
  update(aib, tin[u], dp);
  update(aib, tout[u] + 1, -dp);
  return dp;
}

void testCase() {
  cin >> n;
  for (int i = 1; i < n; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].emplace_back(v);
    g[v].emplace_back(u);
  }
  depth[1] = 1;
  dfs1(1);
  int m;
  cin >> m;
  for (int i = 0; i < m; ++i) {
    int u, v, w;
    cin >> u >> v >> w;
    paths[getLca(u, v)].emplace_back(u, v, w);
  }
  cout << dfs2(1) << '\n';
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int tests = 1;
  for (int tc = 0; tc < tests; ++tc) {
    testCase();
  }
  return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 30
• Subtask 5: 0 / 10
• Subtask 6: 0 / 40