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Submission #30156

# Submission time Handle Problem Language Result Execution time Memory
30156 2017-07-22T17:21:51 Z Andrei1998 Beads and wires (APIO14_beads) C++14
100 / 100
 320 ms 23128 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);
    ios_base :: sync_with_stdio(false);

    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 6 ms 4992 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 5120 KB Output is correct
4 Correct 5 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5040 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 5040 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 5120 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 5120 KB Output is correct
4 Correct 5 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5040 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 5040 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 5120 KB Output is correct
13 Correct 5 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 5 ms 4992 KB Output is correct
16 Correct 5 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 6 ms 4992 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 5120 KB Output is correct
4 Correct 5 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5040 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 5040 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 5120 KB Output is correct
13 Correct 5 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 5 ms 4992 KB Output is correct
16 Correct 5 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 9 ms 5376 KB Output is correct
24 Correct 8 ms 5248 KB Output is correct
25 Correct 9 ms 5376 KB Output is correct
26 Correct 13 ms 5632 KB Output is correct
27 Correct 12 ms 5632 KB Output is correct
28 Correct 12 ms 5888 KB Output is correct
29 Correct 11 ms 5760 KB Output is correct
30 Correct 11 ms 5760 KB Output is correct
31 Correct 12 ms 6272 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4992 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 5120 KB Output is correct
4 Correct 5 ms 4992 KB Output is correct
5 Correct 6 ms 5120 KB Output is correct
6 Correct 6 ms 5040 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 6 ms 4992 KB Output is correct
10 Correct 6 ms 5040 KB Output is correct
11 Correct 5 ms 4992 KB Output is correct
12 Correct 6 ms 5120 KB Output is correct
13 Correct 5 ms 4992 KB Output is correct
14 Correct 6 ms 4992 KB Output is correct
15 Correct 5 ms 4992 KB Output is correct
16 Correct 5 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 9 ms 5376 KB Output is correct
24 Correct 8 ms 5248 KB Output is correct
25 Correct 9 ms 5376 KB Output is correct
26 Correct 13 ms 5632 KB Output is correct
27 Correct 12 ms 5632 KB Output is correct
28 Correct 12 ms 5888 KB Output is correct
29 Correct 11 ms 5760 KB Output is correct
30 Correct 11 ms 5760 KB Output is correct
31 Correct 12 ms 6272 KB Output is correct
32 Correct 48 ms 7788 KB Output is correct
33 Correct 40 ms 7800 KB Output is correct
34 Correct 43 ms 7672 KB Output is correct
35 Correct 295 ms 15708 KB Output is correct
36 Correct 287 ms 15608 KB Output is correct
37 Correct 268 ms 15760 KB Output is correct
38 Correct 250 ms 19044 KB Output is correct
39 Correct 250 ms 18184 KB Output is correct
40 Correct 213 ms 17544 KB Output is correct
41 Correct 320 ms 23128 KB Output is correct