Submission #551622

#	Time	Username	Problem	Language	Result	Execution time	Memory
551622		Soumya1	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	232 ms	31948 KiB

election_campaign

#include <bits/stdc++.h>
#ifdef __LOCAL__
#include <debug_local.h>
#endif
using namespace std;
const int mxN = 1e5 + 5;
const int lg = 18;
vector<int> ad[mxN];
vector<tuple<int, int, int>> ll[mxN];
int par[mxN][lg];
int depth[mxN];
int dp[mxN];
int in[mxN], out[mxN];
int timer;
int t[4 * mxN];
int n;
void update(int x, int lx, int rx, int l, int r, int v) {
  if (l > rx || lx > r) return;
  if (l <= lx && r >= rx) {
    t[x] += v;
    return;
  }
  int mx = (lx + rx) >> 1;
  update(x << 1, lx, mx, l, r, v);
  update(x << 1 | 1, mx + 1, rx, l, r, v);
}
void update(int u, int v) {
  update(1, 1, n, in[u], out[u], v);
}
int query(int x, int lx, int rx, int i) {
  if (lx == rx) return t[x];
  int mx = (lx + rx) >> 1;
  if (i <= mx) return t[x] + query(x << 1, lx, mx, i);
  return t[x] + query(x << 1 | 1, mx + 1, rx, i);
}
int query(int u) {
  return query(1, 1, n, in[u]);
}
void dfs(int u, int p) {
  in[u] = ++timer;
  par[u][0] = p;
  depth[u] = depth[p] + 1;
  for (int i = 1; i < lg; i++) par[u][i] = par[par[u][i - 1]][i - 1];
  for (int v : ad[u]) {
    if (v == p) continue;
    dfs(v, u);
  }
  out[u] = timer;
}
int __lca(int u, int v) {
  if (depth[u] > depth[v]) swap(u, v);
  for (int j = lg - 1; j >= 0; j--) {
    if (depth[par[v][j]] >= depth[u]) v = par[v][j];
  }
  if (u == v) return u;
  for (int j = lg - 1; j >= 0; j--) {
    if (par[v][j] != par[u][j]) u = par[u][j], v = par[v][j];
  }
  return par[v][0];
}
void dfs1(int u, int p) {
  dp[u] = 0;
  int s = 0;
  for (int v : ad[u]) {
    if (v == p) continue;
    dfs1(v, u);
    s += dp[v];
  }
  dp[u] = s;
  for (auto [a, b, c] : ll[u]) {
    dp[u] = max(dp[u], s + query(a) + query(b) + c);
  }
  update(u, s - dp[u]);
}
void testCase() {
  cin >> n;
  for (int i = 1; i < n; i++) {
    int u, v;
    cin >> u >> v;
    ad[u].push_back(v);
    ad[v].push_back(u);
  }
  dfs(1, 0);
  int m;
  cin >> m;
  while (m--) {
    int u, v, c;
    cin >> u >> v >> c;
    int lca = __lca(u, v);
    ll[lca].push_back({u, v, c});
  }
  dfs1(1, 0);
  cout << dp[1] << "\n";
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  testCase();
  return 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