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Submission #563259

# Submission time Handle Problem Language Result Execution time Memory
563259 2022-05-16T16:02:45 Z tranxuanbach Beads and wires (APIO14_beads) C++17
100 / 100
 261 ms 32892 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define endl '\n'
#define fi first
#define se second
#define For(i, l, r) for (auto i = (l); i < (r); i++)
#define ForE(i, l, r) for (auto i = (l); i <= (r); i++)
#define FordE(i, l, r) for (auto i = (l); i >= (r); i--)
#define Fora(v, a) for (auto v: (a))
#define bend(a) (a).begin(), (a).end()
#define isz(a) ((signed)(a).size())

using ll = long long;
using ld = long double;
using pii = pair <int, int>;
using vi = vector <int>;
using vpii = vector <pii>;
using vvi = vector <vi>;

const int N = 2e5 + 5;
const ll infll = (ll)1e18 + 7;

int n;
vpii adj[N];

int wpar[N];

void dfs(int u, int p){
    Fora(&edge, adj[u]){
        int v, w; tie(v, w) = edge;
        if (v == p){
            continue;
        }
        wpar[v] = w;
        dfs(v, u);
    }
}

ll dp[N][2];

void dfs_dp(int u, int p){
    ll sum = 0, mx = -infll;
    Fora(&edge, adj[u]){
        int v, w; tie(v, w) = edge;
        if (v == p){
            continue;
        }
        dfs_dp(v, u);
        sum += dp[v][0];
        mx = max(mx, dp[v][1] - dp[v][0]);
    }
    dp[u][0] = max(sum, sum + mx + wpar[u]);
    dp[u][1] = sum + wpar[u];
}

ll ans = -infll;

void dfs_reroot(int u, int p){
    ans = max(ans, dp[u][0]);

    vector <ll> prefmx(isz(adj[u])), suffmx(isz(adj[u]));

    For(i, 0, isz(adj[u])){
        int v, w; tie(v, w) = adj[u][i];
        prefmx[i] = max(i > 0 ? prefmx[i - 1] : -infll, dp[v][1] - dp[v][0]);
    }
    FordE(i, isz(adj[u]) - 1, 0){
        int v, w; tie(v, w) = adj[u][i];
        suffmx[i] = max(i < isz(adj[u]) - 1 ? suffmx[i + 1] : -infll, dp[v][1] - dp[v][0]);
    }

    int owparu = wpar[u]; ll odpu0 = dp[u][0], odpu1 = dp[u][1], osumu = dp[u][1] - wpar[u];
    For(i, 0, isz(adj[u])){
        int v, w; tie(v, w) = adj[u][i];
        if (v == p){
            continue;
        }
        int owparv = wpar[v]; ll odpv0 = dp[v][0], odpv1 = dp[v][1], osumv = dp[v][1] - wpar[v];
        ll mx = -infll;
        Fora(&edge, adj[v]){
            int tv, tw; tie(tv, tw) = edge;
            if (tv == u){
                continue;
            }
            mx = max(mx, dp[tv][1] - dp[tv][0]);
        }

        wpar[u] = w;
        dp[u][0] = max(osumu - dp[v][0], osumu - dp[v][0] + max(i > 0 ? prefmx[i - 1] : -infll, i < isz(adj[u]) - 1 ? suffmx[i + 1] : -infll) + wpar[u]);
        dp[u][1] = osumu - dp[v][0] + wpar[u];
        wpar[v] = -1e9;
        dp[v][0] = max(osumv + dp[u][0], osumv + dp[u][0] + max(mx, dp[u][1] - dp[u][0]) + wpar[v]);
        dp[v][1] = osumv + dp[u][0] + wpar[v];

        dfs_reroot(v, u);

        wpar[v] = owparv; dp[v][0] = odpv0; dp[v][1] = odpv1;
    }
    wpar[u] = owparu; dp[u][0] = odpu0; dp[u][1] = odpu1;
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    // freopen("KEK.inp", "r", stdin);
    // freopen("KEK.out", "w", stdout);
    cin >> n;
    For(i, 1, n){
        int u, v, w; cin >> u >> v >> w;
        adj[u].emplace_back(v, w);
        adj[v].emplace_back(u, w);
    }

    wpar[1] = -1e9;
    dfs(1, 0);
    dfs_dp(1, 0);
    dfs_reroot(1, 0);

    cout << ans << endl;
}

/*
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INPUT:                                            |
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OUTPUT:                                           |
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*/

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 5076 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 4 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 3 ms 5032 KB Output is correct
11 Correct 4 ms 4948 KB Output is correct
12 Correct 3 ms 4948 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 5076 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 4 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 3 ms 5032 KB Output is correct
11 Correct 4 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 5032 KB Output is correct
14 Correct 3 ms 5036 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 4 ms 5112 KB Output is correct
19 Correct 3 ms 4948 KB Output is correct
20 Correct 3 ms 5012 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 5076 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 4 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 3 ms 5032 KB Output is correct
11 Correct 4 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 5032 KB Output is correct
14 Correct 3 ms 5036 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 4 ms 5112 KB Output is correct
19 Correct 3 ms 4948 KB Output is correct
20 Correct 3 ms 5012 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 4948 KB Output is correct
23 Correct 7 ms 5300 KB Output is correct
24 Correct 6 ms 5392 KB Output is correct
25 Correct 5 ms 5332 KB Output is correct
26 Correct 8 ms 5724 KB Output is correct
27 Correct 9 ms 5716 KB Output is correct
28 Correct 7 ms 5844 KB Output is correct
29 Correct 8 ms 5876 KB Output is correct
30 Correct 8 ms 5808 KB Output is correct
31 Correct 9 ms 6832 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 5076 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 4 ms 4948 KB Output is correct
8 Correct 3 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 3 ms 5032 KB Output is correct
11 Correct 4 ms 4948 KB Output is correct
12 Correct 3 ms 4948 KB Output is correct
13 Correct 3 ms 5032 KB Output is correct
14 Correct 3 ms 5036 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 4 ms 5112 KB Output is correct
19 Correct 3 ms 4948 KB Output is correct
20 Correct 3 ms 5012 KB Output is correct
21 Correct 3 ms 4948 KB Output is correct
22 Correct 3 ms 4948 KB Output is correct
23 Correct 7 ms 5300 KB Output is correct
24 Correct 6 ms 5392 KB Output is correct
25 Correct 5 ms 5332 KB Output is correct
26 Correct 8 ms 5724 KB Output is correct
27 Correct 9 ms 5716 KB Output is correct
28 Correct 7 ms 5844 KB Output is correct
29 Correct 8 ms 5876 KB Output is correct
30 Correct 8 ms 5808 KB Output is correct
31 Correct 9 ms 6832 KB Output is correct
32 Correct 32 ms 8636 KB Output is correct
33 Correct 39 ms 8624 KB Output is correct
34 Correct 39 ms 8644 KB Output is correct
35 Correct 209 ms 19840 KB Output is correct
36 Correct 261 ms 20040 KB Output is correct
37 Correct 231 ms 19832 KB Output is correct
38 Correct 154 ms 23088 KB Output is correct
39 Correct 143 ms 23512 KB Output is correct
40 Correct 162 ms 23004 KB Output is correct
41 Correct 245 ms 32892 KB Output is correct