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Submission #494909

# Submission time Handle Problem Language Result Execution time Memory
494909 2021-12-17T11:43:49 Z Stickfish Beads and wires (APIO14_beads) C++17
100 / 100
 188 ms 22188 KB 
#include <iostream>
#include <vector>
using namespace std;

const int MAXN = 2e5 + 123;
const int INF = 1.77013e9;
vector<pair<int, int>> edg[MAXN];
int dp0[MAXN];
int dp1[MAXN];

void update(int v, int rt) {
    dp0[v] = dp1[v] = 0;
    int rtw = -INF;
    for (auto [u, w] : edg[v]) {
        if (u == rt) {
            rtw = w;
            continue;
        }
        dp0[v] += max(dp0[u], dp1[u]);
    }
    dp1[v] = dp0[v];
    if (rtw != -INF) {
        for (auto [u, w] : edg[v]) {
            if (u == rt)
                continue;
            dp1[v] = max(dp1[v], dp0[v] + rtw + w + min(0, dp0[u] - dp1[u]));
        }
    }
}

void get_ans(int v, int rt) {
    for (auto [u, w] : edg[v]) {
        if (u == rt) {
            continue;
        }
        get_ans(u, v);
    }
    update(v, rt);
}

int dfs(int v, int rt) {
    int dpv0 = dp0[v];
    int dpv1 = dp1[v];
    int ans = dp0[v];
    int a0 = -INF;
    int a1 = -INF;
    for (auto [u, w] : edg[v]) {
        int x = w + min(0, dp0[u] - dp1[u]);
        if (x > a0) {
            a1 = a0;
            a0 = x;
        } else if (x > a1) {
            a1 = x;
        }
    }
    
    for (auto [u, w] : edg[v]) {
        if (u == rt)
            continue;
        int dpu0 = dp0[u];
        int dpu1 = dp1[u];
        dp0[v] -= max(dp0[u], dp1[u]);
        dp1[v] = dp0[v];
        int x = w + min(0, dp0[u] - dp1[u]);
        if (x == a0) {
            if (a1 != -INF)
                dp1[v] = max(dp1[v], dp0[v] + w + a1);
        } else if (a0 != -INF) {
            dp1[v] = max(dp1[v], dp0[v] + w + a0);
        }
        
        update(u, -1);
        ans = max(ans, dfs(u, v));
        dp0[v] = dpv0;
        dp1[v] = dpv1;
        dp0[u] = dpu0;
        dp1[u] = dpu1;
    }
    return ans;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n;
    cin >> n;
    for (int i = 0; i < n - 1; ++i) {
        int u, v, d;
        cin >> u >> v >> d;
        --u, --v;
        edg[u].push_back({v, d});
        edg[v].push_back({u, d});
    }
    get_ans(0, -1);
    int ans = dfs(0, -1);
    cout << ans << '\n';
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 5020 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 5044 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 5016 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 5024 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 5020 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 5020 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 5044 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 5016 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 5024 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 5020 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 5020 KB Output is correct
15 Correct 4 ms 5020 KB Output is correct
16 Correct 3 ms 4940 KB Output is correct
17 Correct 3 ms 5008 KB Output is correct
18 Correct 2 ms 5016 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4952 KB Output is correct
22 Correct 3 ms 4940 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 5020 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 5044 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 5016 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 5024 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 5020 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 5020 KB Output is correct
15 Correct 4 ms 5020 KB Output is correct
16 Correct 3 ms 4940 KB Output is correct
17 Correct 3 ms 5008 KB Output is correct
18 Correct 2 ms 5016 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4952 KB Output is correct
22 Correct 3 ms 4940 KB Output is correct
23 Correct 5 ms 5196 KB Output is correct
24 Correct 5 ms 5196 KB Output is correct
25 Correct 5 ms 5196 KB Output is correct
26 Correct 8 ms 5544 KB Output is correct
27 Correct 8 ms 5580 KB Output is correct
28 Correct 7 ms 5580 KB Output is correct
29 Correct 7 ms 5544 KB Output is correct
30 Correct 7 ms 5580 KB Output is correct
31 Correct 9 ms 5968 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 3 ms 5020 KB Output is correct
3 Correct 3 ms 5020 KB Output is correct
4 Correct 3 ms 5044 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 5020 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 5016 KB Output is correct
9 Correct 3 ms 5024 KB Output is correct
10 Correct 3 ms 5024 KB Output is correct
11 Correct 3 ms 4940 KB Output is correct
12 Correct 3 ms 5020 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 5020 KB Output is correct
15 Correct 4 ms 5020 KB Output is correct
16 Correct 3 ms 4940 KB Output is correct
17 Correct 3 ms 5008 KB Output is correct
18 Correct 2 ms 5016 KB Output is correct
19 Correct 3 ms 5004 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 3 ms 4952 KB Output is correct
22 Correct 3 ms 4940 KB Output is correct
23 Correct 5 ms 5196 KB Output is correct
24 Correct 5 ms 5196 KB Output is correct
25 Correct 5 ms 5196 KB Output is correct
26 Correct 8 ms 5544 KB Output is correct
27 Correct 8 ms 5580 KB Output is correct
28 Correct 7 ms 5580 KB Output is correct
29 Correct 7 ms 5544 KB Output is correct
30 Correct 7 ms 5580 KB Output is correct
31 Correct 9 ms 5968 KB Output is correct
32 Correct 32 ms 7968 KB Output is correct
33 Correct 29 ms 8004 KB Output is correct
34 Correct 34 ms 8100 KB Output is correct
35 Correct 175 ms 16040 KB Output is correct
36 Correct 187 ms 16220 KB Output is correct
37 Correct 188 ms 16036 KB Output is correct
38 Correct 118 ms 16316 KB Output is correct
39 Correct 115 ms 17960 KB Output is correct
40 Correct 122 ms 17784 KB Output is correct
41 Correct 188 ms 22188 KB Output is correct