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Submission #916296

# Submission time Handle Problem Language Result Execution time Memory
916296 2024-01-25T15:37:59 Z Alcabel Beads and wires (APIO14_beads) C++17
100 / 100
 154 ms 26308 KB 
#include <bits/stdc++.h>
using namespace std;

const int maxn = 2e5;
const long long inf = 1e13;
vector<pair<int, int>> g[maxn];
long long dp[maxn][2];

void dfsCalc(int v, int p) {
    dp[v][0] = 0, dp[v][1] = -inf;
    for (const auto& [u, w] : g[v]) {
        if (u != p) {
            dfsCalc(u, v);
            dp[v][0] += max(dp[u][0], dp[u][1] + w);
        }
    }
    for (const auto& [u, w] : g[v]) {
        if (u != p) {
            dp[v][1] = max(dp[v][1], dp[v][0] - max(dp[u][0], dp[u][1] + w) + dp[u][0] + w);
        }
    }
}

long long up[maxn][2];

long long dfsAns(int v, int p, int pw) {
    long long ans, whole;
    ans = whole = dp[v][0] + max(up[v][0], up[v][1] + pw);
    pair<long long, int> max1 = {-inf, -2}, max2 = {-inf, -2}, cur;
    if (p != -1) {
        cur = {-max(up[v][0], up[v][1] + pw) + up[v][0] + pw, -1};
        if (cur >= max1) {
            max2 = max1, max1 = cur;
        } else if (cur > max2) {
            max2 = cur;
        }
    }
    for (const auto& [u, w] : g[v]) {
        if (u != p) {
            cur = {-max(dp[u][0], dp[u][1] + w) + dp[u][0] + w, u};
            if (cur >= max1) {
                max2 = max1, max1 = cur;
            } else if (cur > max2) {
                max2 = cur;
            }
        }
    }
    for (const auto& [u, w] : g[v]) {
        if (u != p) {
            up[u][0] = whole - max(dp[u][0], dp[u][1] + w);
            if (max1.second != u) {
                up[u][1] = up[u][0] + max1.first;
            } else {
                up[u][1] = up[u][0] + max2.first;
            }
            ans = max(ans, dfsAns(u, v, w));
        }
    }
    return ans;
}

void solve() {
    int n;
    cin >> n;
    for (int i = 0; i < n - 1; ++i) {
        int v, u, w;
        cin >> v >> u >> w;
        --v, --u;
        g[v].emplace_back(u, w);
        g[u].emplace_back(v, w);
    }
    dfsCalc(0, -1);
    up[0][0] = up[0][1] = 0;
    cout << dfsAns(0, -1, 0) << '\n';
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    int T = 1;
    cin >> T;
    while (T--) {
        solve();
        cerr << "-----------\n";
        cout << "-----------\n";
    }
#else
    int T = 1;
    // cin >> T;
    while (T--) {
        solve();
    }
#endif

    return 0;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 2 ms 9052 KB Output is correct
4 Correct 2 ms 9052 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 2 ms 9052 KB Output is correct
8 Correct 2 ms 9048 KB Output is correct
9 Correct 2 ms 9052 KB Output is correct
10 Correct 2 ms 9052 KB Output is correct
11 Correct 2 ms 9052 KB Output is correct
12 Correct 2 ms 9052 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 2 ms 9052 KB Output is correct
4 Correct 2 ms 9052 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 2 ms 9052 KB Output is correct
8 Correct 2 ms 9048 KB Output is correct
9 Correct 2 ms 9052 KB Output is correct
10 Correct 2 ms 9052 KB Output is correct
11 Correct 2 ms 9052 KB Output is correct
12 Correct 2 ms 9052 KB Output is correct
13 Correct 2 ms 9052 KB Output is correct
14 Correct 3 ms 9052 KB Output is correct
15 Correct 3 ms 9052 KB Output is correct
16 Correct 3 ms 9052 KB Output is correct
17 Correct 2 ms 9052 KB Output is correct
18 Correct 2 ms 9052 KB Output is correct
19 Correct 3 ms 9052 KB Output is correct
20 Correct 2 ms 9052 KB Output is correct
21 Correct 2 ms 9052 KB Output is correct
22 Correct 2 ms 9052 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 2 ms 9052 KB Output is correct
4 Correct 2 ms 9052 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 2 ms 9052 KB Output is correct
8 Correct 2 ms 9048 KB Output is correct
9 Correct 2 ms 9052 KB Output is correct
10 Correct 2 ms 9052 KB Output is correct
11 Correct 2 ms 9052 KB Output is correct
12 Correct 2 ms 9052 KB Output is correct
13 Correct 2 ms 9052 KB Output is correct
14 Correct 3 ms 9052 KB Output is correct
15 Correct 3 ms 9052 KB Output is correct
16 Correct 3 ms 9052 KB Output is correct
17 Correct 2 ms 9052 KB Output is correct
18 Correct 2 ms 9052 KB Output is correct
19 Correct 3 ms 9052 KB Output is correct
20 Correct 2 ms 9052 KB Output is correct
21 Correct 2 ms 9052 KB Output is correct
22 Correct 2 ms 9052 KB Output is correct
23 Correct 4 ms 9304 KB Output is correct
24 Correct 4 ms 9560 KB Output is correct
25 Correct 4 ms 9308 KB Output is correct
26 Correct 7 ms 9564 KB Output is correct
27 Correct 6 ms 9820 KB Output is correct
28 Correct 5 ms 9820 KB Output is correct
29 Correct 5 ms 9820 KB Output is correct
30 Correct 5 ms 9820 KB Output is correct
31 Correct 6 ms 10076 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 2 ms 9052 KB Output is correct
4 Correct 2 ms 9052 KB Output is correct
5 Correct 2 ms 9052 KB Output is correct
6 Correct 2 ms 9052 KB Output is correct
7 Correct 2 ms 9052 KB Output is correct
8 Correct 2 ms 9048 KB Output is correct
9 Correct 2 ms 9052 KB Output is correct
10 Correct 2 ms 9052 KB Output is correct
11 Correct 2 ms 9052 KB Output is correct
12 Correct 2 ms 9052 KB Output is correct
13 Correct 2 ms 9052 KB Output is correct
14 Correct 3 ms 9052 KB Output is correct
15 Correct 3 ms 9052 KB Output is correct
16 Correct 3 ms 9052 KB Output is correct
17 Correct 2 ms 9052 KB Output is correct
18 Correct 2 ms 9052 KB Output is correct
19 Correct 3 ms 9052 KB Output is correct
20 Correct 2 ms 9052 KB Output is correct
21 Correct 2 ms 9052 KB Output is correct
22 Correct 2 ms 9052 KB Output is correct
23 Correct 4 ms 9304 KB Output is correct
24 Correct 4 ms 9560 KB Output is correct
25 Correct 4 ms 9308 KB Output is correct
26 Correct 7 ms 9564 KB Output is correct
27 Correct 6 ms 9820 KB Output is correct
28 Correct 5 ms 9820 KB Output is correct
29 Correct 5 ms 9820 KB Output is correct
30 Correct 5 ms 9820 KB Output is correct
31 Correct 6 ms 10076 KB Output is correct
32 Correct 20 ms 13916 KB Output is correct
33 Correct 20 ms 13916 KB Output is correct
34 Correct 21 ms 13876 KB Output is correct
35 Correct 154 ms 22384 KB Output is correct
36 Correct 105 ms 22240 KB Output is correct
37 Correct 105 ms 22352 KB Output is correct
38 Correct 84 ms 22612 KB Output is correct
39 Correct 95 ms 22584 KB Output is correct
40 Correct 88 ms 22624 KB Output is correct
41 Correct 151 ms 26308 KB Output is correct