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Submission #908407

# Submission time Handle Problem Language Result Execution time Memory
908407 2024-01-16T11:51:22 Z duckindog Beads and wires (APIO14_beads) C++14
100 / 100
 222 ms 38264 KB 
// from duckindog wth depression
#include<bits/stdc++.h>

using namespace std;

#define int long long

const int N = 2e5 + 10;
int n;
vector<pair<int, int>> ad[N];
int f[2][N];
int pa[N];

void init_dfs(int u, int pre = 0) {

  int all = -1e15, none = -1e15;
  for (auto duck : ad[u]) {
    int v, w; tie(v, w) = duck;
    if (v == pre) continue;
    if (all == -1e15) all = 0;
    pa[v] = w;
    init_dfs(v, u);

    int best = max(f[1][v] + w, f[0][v]);

    all += best;
    none = max(none, f[0][v] + w - best);

  }

  f[0][u] = max(0ll, all);
  f[1][u] = all + none;

}

using pii = pair<int, int>;
int g[2][N];
void dfs(int u, int pre = 0) {

  vector<pii> best;
  int all = 0;

  for (auto duck : ad[u]) {
    int v, w; tie(v, w) = duck;
    if (v == pre) continue;

    best.push_back({v, w});
    all += max(f[1][v] + w, f[0][v]);
  }

  best.push_back({n + 1, -1e8});
  best.push_back({n + 1, -1e8});
  sort(best.begin(), best.end(), [&] (pii a, pii b) {
    int i, j; tie(i, j) = a;
    int t, l; tie(t, l) = b;
    return f[0][i] + j - max(f[0][i], f[1][i] + j) > f[0][t] + l - max(f[0][t], f[1][t] + l);
  });

  pii fi = best[0], se = best[1];


  for (auto duck : ad[u]) {
    int v, w; tie(v, w) = duck;
    if (v == pre) continue;

    int a, b; tie(a, b) = (v == fi.first ? se : fi);

    int sum = all - max(f[1][v] + w, f[0][v]);

    g[0][v] = max(g[0][v], sum - max(f[0][a], f[1][a] + b) + f[0][a] + b + g[0][u] + w);

    g[0][v] = max(g[0][v], max(g[0][u], g[1][u] + w) + sum);

    g[0][v] = max(g[0][v], f[0][u] - max(f[1][v] + w, f[0][v]));

    g[1][v] = f[0][u] - max(f[1][v] + w, f[0][v]) + g[0][u] + w;
    dfs(v, u);
  }


}

int32_t main() {
  cin.tie(0)->sync_with_stdio(0);

  if (fopen("duck.inp", "r")) {
    freopen("duck.inp", "r", stdin);
    freopen("duck.out", "w", stdout);
  }
  g[n + 1][0] = g[n + 1][1] = -1e8;
  cin >> n;
  for (int i = 1; i < n; ++i) {
    int u, v, w; cin >> u >> v >> w;
    ad[u].push_back({v, w});
    ad[v].push_back({u, w});
  }

  init_dfs(1);
  dfs(1);

  int answer = 0;
  for (int i = 1; i <= n; ++i) answer = max(answer, f[0][i] + g[0][i]);

  cout << answer;

}

Compilation message

beads.cpp: In function 'int32_t main()':
beads.cpp:87:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |     freopen("duck.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:88:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |     freopen("duck.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 12888 KB Output is correct
2 Correct 3 ms 12636 KB Output is correct
3 Correct 3 ms 12636 KB Output is correct
4 Correct 4 ms 12636 KB Output is correct
5 Correct 3 ms 12636 KB Output is correct
6 Correct 3 ms 12636 KB Output is correct
7 Correct 3 ms 12636 KB Output is correct
8 Correct 3 ms 12632 KB Output is correct
9 Correct 3 ms 12636 KB Output is correct
10 Correct 3 ms 12636 KB Output is correct
11 Correct 3 ms 12636 KB Output is correct
12 Correct 3 ms 12636 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 12888 KB Output is correct
2 Correct 3 ms 12636 KB Output is correct
3 Correct 3 ms 12636 KB Output is correct
4 Correct 4 ms 12636 KB Output is correct
5 Correct 3 ms 12636 KB Output is correct
6 Correct 3 ms 12636 KB Output is correct
7 Correct 3 ms 12636 KB Output is correct
8 Correct 3 ms 12632 KB Output is correct
9 Correct 3 ms 12636 KB Output is correct
10 Correct 3 ms 12636 KB Output is correct
11 Correct 3 ms 12636 KB Output is correct
12 Correct 3 ms 12636 KB Output is correct
13 Correct 3 ms 12636 KB Output is correct
14 Correct 3 ms 12804 KB Output is correct
15 Correct 4 ms 12636 KB Output is correct
16 Correct 3 ms 12636 KB Output is correct
17 Correct 4 ms 12636 KB Output is correct
18 Correct 3 ms 12816 KB Output is correct
19 Correct 3 ms 12632 KB Output is correct
20 Correct 3 ms 12636 KB Output is correct
21 Correct 3 ms 12632 KB Output is correct
22 Correct 3 ms 12636 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 12888 KB Output is correct
2 Correct 3 ms 12636 KB Output is correct
3 Correct 3 ms 12636 KB Output is correct
4 Correct 4 ms 12636 KB Output is correct
5 Correct 3 ms 12636 KB Output is correct
6 Correct 3 ms 12636 KB Output is correct
7 Correct 3 ms 12636 KB Output is correct
8 Correct 3 ms 12632 KB Output is correct
9 Correct 3 ms 12636 KB Output is correct
10 Correct 3 ms 12636 KB Output is correct
11 Correct 3 ms 12636 KB Output is correct
12 Correct 3 ms 12636 KB Output is correct
13 Correct 3 ms 12636 KB Output is correct
14 Correct 3 ms 12804 KB Output is correct
15 Correct 4 ms 12636 KB Output is correct
16 Correct 3 ms 12636 KB Output is correct
17 Correct 4 ms 12636 KB Output is correct
18 Correct 3 ms 12816 KB Output is correct
19 Correct 3 ms 12632 KB Output is correct
20 Correct 3 ms 12636 KB Output is correct
21 Correct 3 ms 12632 KB Output is correct
22 Correct 3 ms 12636 KB Output is correct
23 Correct 6 ms 13144 KB Output is correct
24 Correct 5 ms 13148 KB Output is correct
25 Correct 5 ms 12940 KB Output is correct
26 Correct 7 ms 13404 KB Output is correct
27 Correct 7 ms 13404 KB Output is correct
28 Correct 8 ms 13708 KB Output is correct
29 Correct 7 ms 13912 KB Output is correct
30 Correct 7 ms 13660 KB Output is correct
31 Correct 8 ms 14428 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 12888 KB Output is correct
2 Correct 3 ms 12636 KB Output is correct
3 Correct 3 ms 12636 KB Output is correct
4 Correct 4 ms 12636 KB Output is correct
5 Correct 3 ms 12636 KB Output is correct
6 Correct 3 ms 12636 KB Output is correct
7 Correct 3 ms 12636 KB Output is correct
8 Correct 3 ms 12632 KB Output is correct
9 Correct 3 ms 12636 KB Output is correct
10 Correct 3 ms 12636 KB Output is correct
11 Correct 3 ms 12636 KB Output is correct
12 Correct 3 ms 12636 KB Output is correct
13 Correct 3 ms 12636 KB Output is correct
14 Correct 3 ms 12804 KB Output is correct
15 Correct 4 ms 12636 KB Output is correct
16 Correct 3 ms 12636 KB Output is correct
17 Correct 4 ms 12636 KB Output is correct
18 Correct 3 ms 12816 KB Output is correct
19 Correct 3 ms 12632 KB Output is correct
20 Correct 3 ms 12636 KB Output is correct
21 Correct 3 ms 12632 KB Output is correct
22 Correct 3 ms 12636 KB Output is correct
23 Correct 6 ms 13144 KB Output is correct
24 Correct 5 ms 13148 KB Output is correct
25 Correct 5 ms 12940 KB Output is correct
26 Correct 7 ms 13404 KB Output is correct
27 Correct 7 ms 13404 KB Output is correct
28 Correct 8 ms 13708 KB Output is correct
29 Correct 7 ms 13912 KB Output is correct
30 Correct 7 ms 13660 KB Output is correct
31 Correct 8 ms 14428 KB Output is correct
32 Correct 25 ms 16220 KB Output is correct
33 Correct 30 ms 16304 KB Output is correct
34 Correct 31 ms 16208 KB Output is correct
35 Correct 160 ms 26696 KB Output is correct
36 Correct 204 ms 27008 KB Output is correct
37 Correct 222 ms 26704 KB Output is correct
38 Correct 128 ms 35056 KB Output is correct
39 Correct 171 ms 30116 KB Output is correct
40 Correct 151 ms 29360 KB Output is correct
41 Correct 214 ms 38264 KB Output is correct