Submission #640203

#	Time	Username	Problem	Language	Result	Execution time	Memory
640203		iee	Putovanje (COCI20_putovanje)	C++17	110 / 110	156 ms	27268 KiB

putovanje

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5, Log = 20;
using ll = long long;
int n, a[N], b[N], c1[N], c2[N];
vector<tuple<int, int, int>> e[N];
ll ans;
int d[N];
int anc[N][Log];
int wc1[N], wc2[N];
int dep[N];
void dfs1(int u, int fa) {
  anc[u][0] = fa;
  dep[u] = dep[fa] + 1;
  for (int i = 1; i < Log; ++i) anc[u][i] = anc[anc[u][i - 1]][i - 1];
  for (auto ver: e[u]) {
    int v, C1, C2;
    tie(v, C1, C2) = ver;
    if (v == fa) continue;
    wc1[v] = C1;
    wc2[v] = C2;
    dfs1(v, u);
  }
}
int lca(int u, int v) {
  if (dep[u] < dep[v])
    swap(u, v);
  for (int i = Log - 1; i >= 0; --i)
    if (dep[anc[u][i]] >= dep[v])
      u = anc[u][i];
  if (u == v) return u;
  for (int i = Log - 1; i >= 0; --i)
    if (anc[u][i] != anc[v][i])
      u = anc[u][i], v = anc[v][i];
  return anc[u][0];
}
void dfs2(int u, int fa) {
  for (auto ver: e[u]) {
    int v = get<0>(ver);
    if (v != fa)
      dfs2(v, u), d[u] += d[v];
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n - 1; ++i) {
    scanf("%d%d%d%d", a+i, b+i, c1+i, c2+i);
    e[a[i]].emplace_back(b[i], c1[i], c2[i]);
    e[b[i]].emplace_back(a[i], c1[i], c2[i]);
  }
  dfs1(1, 0);
  for (int i = 1; i <= n - 1; ++i) {
    const int u = i, v = i + 1;
    d[u] += 1, d[v] += 1, d[lca(u, v)] -= 2;
  }
  dfs2(1, 0);
  for (int i = 2; i <= n; ++i)
    ans += min((ll) wc2[i], 1ll * wc1[i] * d[i]);
  cout << ans;
  return 0;
}

Compilation message (stderr)

putovanje.cpp: In function 'int main()':
putovanje.cpp:45:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |   scanf("%d", &n);
      |   ~~~~~^~~~~~~~~~
putovanje.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     scanf("%d%d%d%d", a+i, b+i, c1+i, c2+i);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 65 / 65