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Submission #883280

# Submission time Handle Problem Language Result Execution time Memory
883280 2023-12-05T04:02:34 Z nguyentunglam Beads and wires (APIO14_beads) C++17
100 / 100
 115 ms 26096 KB 
#include<bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define endl "\n"
using namespace std;

const int N = 2e5 + 10;

int f[N], g[N], h[N];

int _f[N], _g[N], _h[N];

int maxw[2][N];

vector<pair<int, int> > adj[N];

void dfs(int u, int p) {
  maxw[0][u] = maxw[1][u] = -1e9;
  for(auto &[v, w] : adj[u]) if (v != p) {
    dfs(v, u);
    h[v] = max(f[v], g[v] + w);
    f[u] += h[v];
    maxw[1][u] = max(maxw[1][u], w + f[v] - h[v]);
    if (maxw[0][u] < maxw[1][u]) swap(maxw[0][u], maxw[1][u]);
  }
  g[u] = f[u] + maxw[0][u];
}

void _dfs(int u, int p, int w, int pre_cost) {
  if (p) {
    _f[u] = f[p] - h[u] + _h[p];
    int cost = maxw[0][p];
    if (w + f[u] - h[u] == cost) cost = maxw[1][p];
    cost = max(cost, pre_cost);
    _g[u] = _f[u] + cost;
    _h[u] = max(_f[u], _g[u] + w);
    int new_cost = w + _f[u] - _h[u];
    pre_cost = new_cost;
  }

  for(auto &[v, next_w] : adj[u]) if (v != p) {
    _dfs(v, u, next_w, pre_cost);
  }
}

int32_t main() {
  #define task ""

  cin.tie(0) -> sync_with_stdio(0);

  if (fopen("task.inp", "r")) {
    freopen("task.inp", "r", stdin);
    freopen("task.out", "w", stdout);
  }

  if (fopen(task".inp", "r")) {
    freopen (task".inp", "r", stdin);
    freopen (task".out", "w", stdout);
  }

  int n; cin >> n;

  for(int i = 1; i < n; i++) {
    int a, b, c; cin >> a >> b >> c;
    adj[a].emplace_back(b, c);
    adj[b].emplace_back(a, c);
  }

  dfs(1, 0);

  _dfs(1, 0, 0, -1e9);

  int ans = 0;

  for(int i = 1; i <= n; i++) {
    ans = max(ans, f[i] + _h[i]);
  }

  cout << ans;
}

Compilation message

beads.cpp: In function 'int32_t main()':
beads.cpp:51:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |     freopen("task.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:52:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |     freopen("task.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:56:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     freopen (task".inp", "r", stdin);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
beads.cpp:57:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |     freopen (task".out", "w", stdout);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8792 KB Output is correct
2 Correct 2 ms 8796 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 1 ms 8796 KB Output is correct
5 Correct 2 ms 8796 KB Output is correct
6 Correct 2 ms 8796 KB Output is correct
7 Correct 1 ms 8796 KB Output is correct
8 Correct 1 ms 8792 KB Output is correct
9 Correct 2 ms 8796 KB Output is correct
10 Correct 2 ms 8796 KB Output is correct
11 Correct 1 ms 8796 KB Output is correct
12 Correct 2 ms 8796 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8792 KB Output is correct
2 Correct 2 ms 8796 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 1 ms 8796 KB Output is correct
5 Correct 2 ms 8796 KB Output is correct
6 Correct 2 ms 8796 KB Output is correct
7 Correct 1 ms 8796 KB Output is correct
8 Correct 1 ms 8792 KB Output is correct
9 Correct 2 ms 8796 KB Output is correct
10 Correct 2 ms 8796 KB Output is correct
11 Correct 1 ms 8796 KB Output is correct
12 Correct 2 ms 8796 KB Output is correct
13 Correct 2 ms 8796 KB Output is correct
14 Correct 2 ms 8796 KB Output is correct
15 Correct 2 ms 8796 KB Output is correct
16 Correct 2 ms 8796 KB Output is correct
17 Correct 2 ms 8796 KB Output is correct
18 Correct 2 ms 8796 KB Output is correct
19 Correct 2 ms 8796 KB Output is correct
20 Correct 2 ms 9048 KB Output is correct
21 Correct 2 ms 8796 KB Output is correct
22 Correct 2 ms 8796 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8792 KB Output is correct
2 Correct 2 ms 8796 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 1 ms 8796 KB Output is correct
5 Correct 2 ms 8796 KB Output is correct
6 Correct 2 ms 8796 KB Output is correct
7 Correct 1 ms 8796 KB Output is correct
8 Correct 1 ms 8792 KB Output is correct
9 Correct 2 ms 8796 KB Output is correct
10 Correct 2 ms 8796 KB Output is correct
11 Correct 1 ms 8796 KB Output is correct
12 Correct 2 ms 8796 KB Output is correct
13 Correct 2 ms 8796 KB Output is correct
14 Correct 2 ms 8796 KB Output is correct
15 Correct 2 ms 8796 KB Output is correct
16 Correct 2 ms 8796 KB Output is correct
17 Correct 2 ms 8796 KB Output is correct
18 Correct 2 ms 8796 KB Output is correct
19 Correct 2 ms 8796 KB Output is correct
20 Correct 2 ms 9048 KB Output is correct
21 Correct 2 ms 8796 KB Output is correct
22 Correct 2 ms 8796 KB Output is correct
23 Correct 4 ms 9052 KB Output is correct
24 Correct 3 ms 9048 KB Output is correct
25 Correct 4 ms 9048 KB Output is correct
26 Correct 5 ms 9308 KB Output is correct
27 Correct 4 ms 9308 KB Output is correct
28 Correct 4 ms 9308 KB Output is correct
29 Correct 4 ms 9304 KB Output is correct
30 Correct 4 ms 9308 KB Output is correct
31 Correct 5 ms 9564 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8792 KB Output is correct
2 Correct 2 ms 8796 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 1 ms 8796 KB Output is correct
5 Correct 2 ms 8796 KB Output is correct
6 Correct 2 ms 8796 KB Output is correct
7 Correct 1 ms 8796 KB Output is correct
8 Correct 1 ms 8792 KB Output is correct
9 Correct 2 ms 8796 KB Output is correct
10 Correct 2 ms 8796 KB Output is correct
11 Correct 1 ms 8796 KB Output is correct
12 Correct 2 ms 8796 KB Output is correct
13 Correct 2 ms 8796 KB Output is correct
14 Correct 2 ms 8796 KB Output is correct
15 Correct 2 ms 8796 KB Output is correct
16 Correct 2 ms 8796 KB Output is correct
17 Correct 2 ms 8796 KB Output is correct
18 Correct 2 ms 8796 KB Output is correct
19 Correct 2 ms 8796 KB Output is correct
20 Correct 2 ms 9048 KB Output is correct
21 Correct 2 ms 8796 KB Output is correct
22 Correct 2 ms 8796 KB Output is correct
23 Correct 4 ms 9052 KB Output is correct
24 Correct 3 ms 9048 KB Output is correct
25 Correct 4 ms 9048 KB Output is correct
26 Correct 5 ms 9308 KB Output is correct
27 Correct 4 ms 9308 KB Output is correct
28 Correct 4 ms 9308 KB Output is correct
29 Correct 4 ms 9304 KB Output is correct
30 Correct 4 ms 9308 KB Output is correct
31 Correct 5 ms 9564 KB Output is correct
32 Correct 18 ms 11100 KB Output is correct
33 Correct 19 ms 11100 KB Output is correct
34 Correct 19 ms 11328 KB Output is correct
35 Correct 90 ms 18816 KB Output is correct
36 Correct 104 ms 22352 KB Output is correct
37 Correct 106 ms 22612 KB Output is correct
38 Correct 74 ms 22720 KB Output is correct
39 Correct 62 ms 21908 KB Output is correct
40 Correct 76 ms 22456 KB Output is correct
41 Correct 115 ms 26096 KB Output is correct