oj.uz

Submission #231018

# Submission time Handle Problem Language Result Execution time Memory
231018 2020-05-12T11:29:48 Z lyc Beads and wires (APIO14_beads) C++14
100 / 100
 227 ms 27760 KB 
#include <bits/stdc++.h>
using namespace std;

#define TRACE(x) cerr << #x << " :: " << x << endl
#define _ << " " <<
#define SZ(x) (int)(x).size()
#define ALL(x) (x).begin(),(x).end()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for (int i=(a);i>=(b);--i)
using ii=pair<int,int>;
using ll=long long;

const int MX_N = 2e5+5;
const int INF = 2e9+10;

int N;
vector<ii> al[MX_N];

ll f[MX_N][3], g[MX_N][2], ans = 0;

void DFS(int u, int p) {
    ll best[] = {-INF,-INF};
    for (ii v : al[u]) if (v.first != p) {
        DFS(v.first,u);

        ll val = max(f[v.first][0], f[v.first][1]+v.second);
        f[u][0] += val;
        ll x = f[v.first][0]+v.second - val;
        FOR(i,0,1) if (x > best[i]) swap(x,best[i]);
    }
    if (best[0] == -INF) f[u][1] = -INF;
    else f[u][1] = f[u][0] + best[0];
    if (f[u][1] == -INF || best[1] == -INF) f[u][2] = -INF;
    else f[u][2] = f[u][1] + best[1];
    ans = max(ans, f[u][0]);
}

void DFS2(int u, int p) {
    ll sum = 0;
    ll best[] = {-INF,-INF};
    ll bestV[] = {-1,-1};
    for (ii v : al[u]) if (v.first != p) {
        ll val = max(f[v.first][0], f[v.first][1]+v.second);
        sum += val;
        ll x = f[v.first][0]+v.second - val;
        ll y = v.first;
        FOR(i,0,1) if (x > best[i]) swap(x,best[i]), swap(y,bestV[i]);
    }
    for (ii v : al[u]) if (v.first != p) {
        ll val = max(f[v.first][0], f[v.first][1]+v.second);
        g[v.first][0] = max({
                    g[u][0] + (sum-val),
                    v.second + g[u][1] + (sum-val),
                    v.second + g[u][0] + (sum-val) + (bestV[0] == v.first ? best[1] : best[0])
                });
        g[v.first][1] = v.second + g[u][0] + (sum-val),
        DFS2(v.first,u);
    }
    ans = max(ans, f[u][0] + g[u][0]);
    if (f[u][1] != -INF) ans = max(ans, f[u][1] + g[u][1]);
    if (f[u][2] != -INF) ans = max(ans, f[u][2] + g[u][0]);
    //TRACE(u _ g[u][0] _ g[u][1]);
    //TRACE(u _ f[u][0] _ f[u][1] _ f[u][2] _ g[u][0] _ g[u][1]);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> N;
    FOR(i,1,N-1){
        int A, B, C; cin >> A >> B >> C;
        al[A].emplace_back(B,C);
        al[B].emplace_back(A,C);
    }

    DFS(1,0);
    g[1][1] = -INF;
    DFS2(1,0);
    cout << ans;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 5120 KB Output is correct
6 Correct 7 ms 5120 KB Output is correct
7 Correct 7 ms 5120 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 4992 KB Output is correct
10 Correct 7 ms 4992 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 5120 KB Output is correct
6 Correct 7 ms 5120 KB Output is correct
7 Correct 7 ms 5120 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 4992 KB Output is correct
10 Correct 7 ms 4992 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 7 ms 4992 KB Output is correct
14 Correct 7 ms 4992 KB Output is correct
15 Correct 7 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 7 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 7 ms 5120 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 5120 KB Output is correct
6 Correct 7 ms 5120 KB Output is correct
7 Correct 7 ms 5120 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 4992 KB Output is correct
10 Correct 7 ms 4992 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 7 ms 4992 KB Output is correct
14 Correct 7 ms 4992 KB Output is correct
15 Correct 7 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 7 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 7 ms 5120 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 10 ms 5504 KB Output is correct
24 Correct 9 ms 5504 KB Output is correct
25 Correct 10 ms 5504 KB Output is correct
26 Correct 12 ms 5888 KB Output is correct
27 Correct 12 ms 6016 KB Output is correct
28 Correct 13 ms 6016 KB Output is correct
29 Correct 11 ms 6016 KB Output is correct
30 Correct 11 ms 6016 KB Output is correct
31 Correct 12 ms 6400 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 7 ms 4992 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 5120 KB Output is correct
6 Correct 7 ms 5120 KB Output is correct
7 Correct 7 ms 5120 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 4992 KB Output is correct
10 Correct 7 ms 4992 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 7 ms 4992 KB Output is correct
14 Correct 7 ms 4992 KB Output is correct
15 Correct 7 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 7 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 7 ms 5120 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 10 ms 5504 KB Output is correct
24 Correct 9 ms 5504 KB Output is correct
25 Correct 10 ms 5504 KB Output is correct
26 Correct 12 ms 5888 KB Output is correct
27 Correct 12 ms 6016 KB Output is correct
28 Correct 13 ms 6016 KB Output is correct
29 Correct 11 ms 6016 KB Output is correct
30 Correct 11 ms 6016 KB Output is correct
31 Correct 12 ms 6400 KB Output is correct
32 Correct 40 ms 9600 KB Output is correct
33 Correct 39 ms 9720 KB Output is correct
34 Correct 44 ms 9600 KB Output is correct
35 Correct 227 ms 23800 KB Output is correct
36 Correct 211 ms 23928 KB Output is correct
37 Correct 205 ms 23800 KB Output is correct
38 Correct 146 ms 24292 KB Output is correct
39 Correct 141 ms 24408 KB Output is correct
40 Correct 146 ms 24268 KB Output is correct
41 Correct 204 ms 27760 KB Output is correct