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Submission #30155

# Submission time Handle Problem Language Result Execution time Memory
30155 2017-07-22T17:20:20 Z Andrei1998 Beads and wires (APIO14_beads) C++14
100 / 100
 456 ms 23140 KB 
#include <bits/stdc++.h>

using namespace std;

const int NMAX = 200000 + 5;
const int INF = 2E9 + 15;

int N;
vector <pair <int, int> > graph[NMAX];
int fatherEdgeCost[NMAX];

int dp[NMAX][2];
void dfs1(int node, int father) {
    dp[node][0] = 0;
    dp[node][1] = -INF;
    for (auto it: graph[node])
        if (it.first != father) {
            dfs1(it.first, node);
            int val = max(dp[it.first][0], dp[it.first][1] + it.second);
            dp[node][0] += val;
            dp[node][1] = max(dp[node][1], it.second + dp[it.first][0] - val);
        }
    dp[node][1] = dp[node][0] + dp[node][1];
}

int ans;
int getBestNotNode(const vector <pair <int, int> > &v, int node) {
    for (int i = 0; i < v.size(); ++ i)
        if (v[i].second != node)
            return v[i].first;
    return -INF;
}

int up[NMAX][2];
void dfs2(int node, int father, int edge) {
    int cost = dp[node][0] + max(up[node][0], up[node][1] + edge);
    ans = max(ans, cost);

    vector <pair <int, int> > v;
    if (father)
        v.push_back(make_pair(up[node][0] + edge - max(up[node][0], up[node][1] + edge), father));

    for (auto it: graph[node])
        if (it.first != father) {
            int val = max(dp[it.first][0], dp[it.first][1] + it.second);
            up[it.first][0] = dp[node][0] - val + max(up[node][0], up[node][1] + edge);
            v.push_back(make_pair(it.second + dp[it.first][0] - val, it.first));
        }

    sort(v.begin(), v.end(), greater <pair <int, int> >());
    if (v.size() > 2)
        v.resize(2);

    for (auto it: graph[node])
        if (it.first != father) {
            int val = max(dp[it.first][0], dp[it.first][1] + it.second);
            up[it.first][1] = cost + getBestNotNode(v, it.first) - val;
        }
    for (auto it: graph[node])
        if (it.first != father)
            dfs2(it.first, node, it.second);
}

int main()
{
    //freopen("data.in", "r", stdin);
    cin >> N;
    for (int i = 1; i < N; ++ i) {
        int a, b, c;
        cin >> a >> b >> c;
        graph[a].push_back({b, c});
        graph[b].push_back({a, c});
    }

    dfs1(1, 0);
    dfs2(1, 0, 0);

    cout << ans << '\n';
    return 0;
}

Compilation message

beads.cpp: In function 'int getBestNotNode(const std::vector<std::pair<int, int> >&, int)':
beads.cpp:28:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < v.size(); ++ i)
                     ~~^~~~~~~~~~

Subtask #1
13.0 / 13.0

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

Subtask #2
15.0 / 15.0

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

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 7 ms 4992 KB Output is correct
5 Correct 6 ms 4992 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 6 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct
13 Correct 7 ms 5120 KB Output is correct
14 Correct 6 ms 5120 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 5120 KB Output is correct
23 Correct 12 ms 5376 KB Output is correct
24 Correct 12 ms 5376 KB Output is correct
25 Correct 11 ms 5244 KB Output is correct
26 Correct 18 ms 5564 KB Output is correct
27 Correct 17 ms 5632 KB Output is correct
28 Correct 20 ms 5760 KB Output is correct
29 Correct 17 ms 5752 KB Output is correct
30 Correct 18 ms 5632 KB Output is correct
31 Correct 18 ms 6272 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 7 ms 4992 KB Output is correct
5 Correct 6 ms 4992 KB Output is correct
6 Correct 6 ms 4992 KB Output is correct
7 Correct 6 ms 4992 KB Output is correct
8 Correct 5 ms 4992 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 4992 KB Output is correct
11 Correct 6 ms 4992 KB Output is correct
12 Correct 6 ms 4992 KB Output is correct
13 Correct 7 ms 5120 KB Output is correct
14 Correct 6 ms 5120 KB Output is correct
15 Correct 6 ms 5120 KB Output is correct
16 Correct 6 ms 5120 KB Output is correct
17 Correct 6 ms 5120 KB Output is correct
18 Correct 6 ms 5120 KB Output is correct
19 Correct 6 ms 5120 KB Output is correct
20 Correct 6 ms 5120 KB Output is correct
21 Correct 6 ms 5120 KB Output is correct
22 Correct 6 ms 5120 KB Output is correct
23 Correct 12 ms 5376 KB Output is correct
24 Correct 12 ms 5376 KB Output is correct
25 Correct 11 ms 5244 KB Output is correct
26 Correct 18 ms 5564 KB Output is correct
27 Correct 17 ms 5632 KB Output is correct
28 Correct 20 ms 5760 KB Output is correct
29 Correct 17 ms 5752 KB Output is correct
30 Correct 18 ms 5632 KB Output is correct
31 Correct 18 ms 6272 KB Output is correct
32 Correct 83 ms 7692 KB Output is correct
33 Correct 81 ms 7928 KB Output is correct
34 Correct 80 ms 7672 KB Output is correct
35 Correct 444 ms 15600 KB Output is correct
36 Correct 433 ms 15660 KB Output is correct
37 Correct 456 ms 15700 KB Output is correct
38 Correct 333 ms 19072 KB Output is correct
39 Correct 339 ms 18404 KB Output is correct
40 Correct 345 ms 17624 KB Output is correct
41 Correct 455 ms 23140 KB Output is correct