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Submission #543806

# Submission time Handle Problem Language Result Execution time Memory
543806 2022-03-31T12:18:00 Z inventiontime Beads and wires (APIO14_beads) C++17
100 / 100
 205 ms 32796 KB 
// [node][0] is current node is *ordinary*
// [node][1] is current node is *connector* 
// connector: node between two blue wires
// condition for connector: 
    // atleast one child node is ordinary

#include <bits/stdc++.h>
using namespace std;

#define int ll
//#define endl '\n'

#define fast_io ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define pb push_back
#define re resize
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define loop(i, n) for(int i = 0; i < n; i++)
#define loop1(i, n) for(int i = 1; i <= n; i++)
#define print(x) cout << #x << ": " << x << endl

typedef long long ll;
typedef vector<int> vi;
typedef array<int, 2> ii;
typedef array<int, 3> ti;
typedef vector<ii> vii;
typedef vector<ti> vti;
typedef priority_queue<int> pq;

template<class T> bool ckmin(T&a, T b) { bool B = a > b; a = min(a, b); return B; }
template<class T> bool ckmax(T&a, T b) { bool B = a < b; a = max(a, b); return B; }

const int inf = 1e17;
const int maxn = 2e5 + 5;

int n;
vii adj[maxn];
ii sub[maxn];
ii min_diff[maxn];
ii min_diff2[maxn];

void calc_dfs(int u, int p) {

    for(auto [v, w] : adj[u]) if(v != p)
        calc_dfs(v, u);

    sub[u][0] = 0;
    sub[u][1] = 0;
    min_diff[u] = {inf, -1};
    for(auto [v, w] : adj[u]) if(v != p) {
        sub[u][0] += max(sub[v][0], sub[v][1] + w);
        sub[u][1] += max(sub[v][0], sub[v][1] + w);
        ii min_d = {max(sub[v][0], sub[v][1] + w) - (sub[v][0] + w), v};
        if(min_d <= min_diff[u]) {
            min_diff2[u] = min_diff[u];
            min_diff[u] = min_d;
        } else if(min_d < min_diff2[u]) {
            min_diff2[u] = min_d;
        }
    }
    sub[u][1] -= min_diff[u][0];

}

void move(int u, int v, int w) {

    ii sub_u = sub[u];
    ii sub_v = sub[v];

    sub[u][0] -= max(sub_v[0], sub_v[1] + w);
    sub[u][1] -= max(sub_v[0], sub_v[1] + w);
    if(min_diff[u][1] == v) {
        sub[u][1] += min_diff[u][0];
        sub[u][1] -= min_diff2[u][0];
    }

    sub[v][0] += max(sub[u][0], sub[u][1] + w);
    sub[v][1] += max(sub[u][0], sub[u][1] + w);
    if(min_diff[v][1] == u) sub[v][1] += min_diff2[v][0];
    else sub[v][1] += min_diff[v][0];

    ii min_d = {max(sub[u][0], sub[u][1] + w) - (sub[u][0] + w), u};
    if(min_d <= min_diff[v]) {
        min_diff2[v] = min_diff[v];
        min_diff[v] = min_d;
    } else if(min_d < min_diff2[v]) {
        min_diff2[v] = min_d;
    }
    sub[v][1] -= min_diff[v][0];

}

int dfs(int u, int p) {

    int res = sub[u][0];
    for(auto [v, w] : adj[u]) if(v != p) {
        move(u, v, w);
        ckmax(res, dfs(v, u));
        move(v, u, w);
    }

    return res;

}

void solve() {
    
    cin >> n;
    loop(i, n-1) {
        int u, v, w; cin >> u >> v >> w;
        adj[u].pb({v, w});
        adj[v].pb({u, w});
    }

    calc_dfs(1, 1);
    cout << dfs(1, 1) << endl;

}

signed main() {

    fast_io;

    int t = 1; //cin >> t;
    while(t--)
        solve();

    //cout << flush;

    return 0;

}

Compilation message

beads.cpp: In function 'void move(ll, ll, ll)':
beads.cpp:68:8: warning: variable 'sub_u' set but not used [-Wunused-but-set-variable]
   68 |     ii sub_u = sub[u];
      |        ^~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 2 ms 5028 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 2 ms 5028 KB Output is correct
13 Correct 3 ms 5028 KB Output is correct
14 Correct 3 ms 5076 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 5024 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 4948 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 2 ms 5028 KB Output is correct
13 Correct 3 ms 5028 KB Output is correct
14 Correct 3 ms 5076 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 5024 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 4948 KB Output is correct
23 Correct 5 ms 5588 KB Output is correct
24 Correct 5 ms 5588 KB Output is correct
25 Correct 5 ms 5588 KB Output is correct
26 Correct 8 ms 6100 KB Output is correct
27 Correct 10 ms 6180 KB Output is correct
28 Correct 6 ms 6096 KB Output is correct
29 Correct 6 ms 6100 KB Output is correct
30 Correct 6 ms 6060 KB Output is correct
31 Correct 9 ms 6484 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 4948 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 3 ms 4948 KB Output is correct
12 Correct 2 ms 5028 KB Output is correct
13 Correct 3 ms 5028 KB Output is correct
14 Correct 3 ms 5076 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 5024 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 3 ms 4948 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4948 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 4948 KB Output is correct
23 Correct 5 ms 5588 KB Output is correct
24 Correct 5 ms 5588 KB Output is correct
25 Correct 5 ms 5588 KB Output is correct
26 Correct 8 ms 6100 KB Output is correct
27 Correct 10 ms 6180 KB Output is correct
28 Correct 6 ms 6096 KB Output is correct
29 Correct 6 ms 6100 KB Output is correct
30 Correct 6 ms 6060 KB Output is correct
31 Correct 9 ms 6484 KB Output is correct
32 Correct 35 ms 10660 KB Output is correct
33 Correct 30 ms 10668 KB Output is correct
34 Correct 33 ms 10596 KB Output is correct
35 Correct 205 ms 28176 KB Output is correct
36 Correct 193 ms 28180 KB Output is correct
37 Correct 203 ms 28236 KB Output is correct
38 Correct 130 ms 27500 KB Output is correct
39 Correct 121 ms 27236 KB Output is correct
40 Correct 133 ms 27432 KB Output is correct
41 Correct 184 ms 32796 KB Output is correct