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Submission #31624

# Submission time Handle Problem Language Result Execution time Memory
31624 2017-08-30T04:02:00 Z minkank Beads and wires (APIO14_beads) C++14
100 / 100
 854 ms 103244 KB 
#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> ii;

const int N = 2e5 + 5;

int n, dp[N][2], ans, g[N][2], cnt[N];
vector<ii> a[N], b[N];
vector<int> l[N], r[N], sax[2][N], cax[2][N];

void dfs(int u, int p) {
    dp[u][0] = dp[u][1] = 0;
    cnt[u] = 0;
    for(int i = 0; i < a[u].size(); ++i) {
        int v = a[u][i].first;
        if(v == p) continue;
        dfs(v, u);
        cnt[u]++; b[u][cnt[u]] = a[u][i];
    }
    l[u][0] = 0;
    for(int i = 1; i <= cnt[u]; ++i) {
        int v = b[u][i].first, w = b[u][i].second;
        l[u][i] = l[u][i - 1] + max(dp[v][1] + w, dp[v][0]);
    }
    r[u][cnt[u] + 1] = 0;
    for(int i = cnt[u]; i >= 1; --i) {
        int v = b[u][i].first, w = b[u][i].second;
        r[u][i] = r[u][i + 1] + max(dp[v][1] + w, dp[v][0]);
    }
    dp[u][0] = l[u][cnt[u]];
    for(int i = 1; i <= cnt[u]; ++i) {
        int v = b[u][i].first, w = b[u][i].second;
        dp[u][1] = max(dp[u][1], l[u][i - 1] + r[u][i + 1] + dp[v][0] + w);
    }
    if(a[u].size() == 1) dp[u][1] = -1e9;
}

void redfs(int u, int p) {
    //if(u == 3) cout << g[p][0] << ' ' << g[p][1] << endl;
    if(a[p].size() == 1) g[p][1] = -1e9;
    sax[1][u][0] = -1e9;
    for(int i = 1; i <= cnt[u]; ++i) {
        int v = b[u][i].first, w = b[u][i].second;
        sax[0][u][i] = sax[0][u][i - 1] + max(dp[v][1] + w, dp[v][0]);
        sax[1][u][i] = sax[0][u][i - 1] + w + dp[v][0];
        sax[1][u][i] = max(sax[1][u][i], sax[1][u][i - 1] + max(dp[v][1] + w, dp[v][0]));
    }
    int W = 0;
    for(int i = 0; i < a[u].size(); ++i) if(a[u][i].first == p) W = a[u][i].second;
    if(u != 1) {
        cax[0][u][cnt[u] + 1] = max(g[p][1] + W, g[p][0]);
        cax[1][u][cnt[u] + 1] = W + g[p][0];
    }
    else cax[0][u][cnt[u] + 1] = 0, cax[1][u][cnt[u] + 1] = -1e9;
    for(int i = cnt[u]; i >= 1; --i) {
        int v = b[u][i].first, w = b[u][i].second;
        cax[0][u][i] = cax[0][u][i + 1] + max(dp[v][1] + w, dp[v][0]);
        cax[1][u][i] = cax[0][u][i + 1] + w + dp[v][0];
        cax[1][u][i] = max(cax[1][u][i], cax[1][u][i + 1] + max(dp[v][1] + w, dp[v][0]));
    }
    ans = max(ans, cax[0][u][1]);
    for(int i = 1; i <= cnt[u]; ++i) {
        int v = b[u][i].first;
        g[u][0] = sax[0][u][i - 1] + cax[0][u][i + 1];
        g[u][1] = max(sax[1][u][i - 1] + cax[0][u][i + 1], sax[0][u][i - 1] + cax[1][u][i + 1]);
        redfs(v, u);
    }
}

int main() {
    cin >> n;
    for(int i = 1; i < n; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        a[u].push_back(ii(v, w));
        a[v].push_back(ii(u, w));
    }
    for(int i = 1; i <= n; ++i) l[i].assign(a[i].size() + 3, 0), r[i].assign(a[i].size() + 3, 0), b[i].assign(a[i].size() + 3, ii(0, 0)), sax[0][i].assign(a[i].size() + 3, 0), sax[1][i].assign(a[i].size() + 3, 0), cax[0][i].assign(a[i].size() + 3, 0), cax[1][i].assign(a[i].size() + 3, 0);
    dfs(1, 1);
    redfs(1, 1);
    cout << ans;
}

Compilation message

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:15:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < a[u].size(); ++i) {
                    ~~^~~~~~~~~~~~~
beads.cpp: In function 'void redfs(int, int)':
beads.cpp:50:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < a[u].size(); ++i) if(a[u][i].first == p) W = a[u][i].second;
                    ~~^~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 37884 KB Output is correct
2 Correct 35 ms 37880 KB Output is correct
3 Correct 34 ms 37880 KB Output is correct
4 Correct 34 ms 38008 KB Output is correct
5 Correct 34 ms 37888 KB Output is correct
6 Correct 35 ms 37880 KB Output is correct
7 Correct 54 ms 37940 KB Output is correct
8 Correct 35 ms 37880 KB Output is correct
9 Correct 34 ms 37880 KB Output is correct
10 Correct 34 ms 37880 KB Output is correct
11 Correct 35 ms 37880 KB Output is correct
12 Correct 34 ms 38008 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 37884 KB Output is correct
2 Correct 35 ms 37880 KB Output is correct
3 Correct 34 ms 37880 KB Output is correct
4 Correct 34 ms 38008 KB Output is correct
5 Correct 34 ms 37888 KB Output is correct
6 Correct 35 ms 37880 KB Output is correct
7 Correct 54 ms 37940 KB Output is correct
8 Correct 35 ms 37880 KB Output is correct
9 Correct 34 ms 37880 KB Output is correct
10 Correct 34 ms 37880 KB Output is correct
11 Correct 35 ms 37880 KB Output is correct
12 Correct 34 ms 38008 KB Output is correct
13 Correct 34 ms 38008 KB Output is correct
14 Correct 34 ms 37980 KB Output is correct
15 Correct 33 ms 37888 KB Output is correct
16 Correct 35 ms 38008 KB Output is correct
17 Correct 35 ms 38008 KB Output is correct
18 Correct 35 ms 38008 KB Output is correct
19 Correct 34 ms 38016 KB Output is correct
20 Correct 34 ms 37956 KB Output is correct
21 Correct 35 ms 38008 KB Output is correct
22 Correct 36 ms 37988 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 37884 KB Output is correct
2 Correct 35 ms 37880 KB Output is correct
3 Correct 34 ms 37880 KB Output is correct
4 Correct 34 ms 38008 KB Output is correct
5 Correct 34 ms 37888 KB Output is correct
6 Correct 35 ms 37880 KB Output is correct
7 Correct 54 ms 37940 KB Output is correct
8 Correct 35 ms 37880 KB Output is correct
9 Correct 34 ms 37880 KB Output is correct
10 Correct 34 ms 37880 KB Output is correct
11 Correct 35 ms 37880 KB Output is correct
12 Correct 34 ms 38008 KB Output is correct
13 Correct 34 ms 38008 KB Output is correct
14 Correct 34 ms 37980 KB Output is correct
15 Correct 33 ms 37888 KB Output is correct
16 Correct 35 ms 38008 KB Output is correct
17 Correct 35 ms 38008 KB Output is correct
18 Correct 35 ms 38008 KB Output is correct
19 Correct 34 ms 38016 KB Output is correct
20 Correct 34 ms 37956 KB Output is correct
21 Correct 35 ms 38008 KB Output is correct
22 Correct 36 ms 37988 KB Output is correct
23 Correct 43 ms 39500 KB Output is correct
24 Correct 45 ms 39504 KB Output is correct
25 Correct 44 ms 39416 KB Output is correct
26 Correct 56 ms 40956 KB Output is correct
27 Correct 57 ms 41080 KB Output is correct
28 Correct 55 ms 41080 KB Output is correct
29 Correct 58 ms 41080 KB Output is correct
30 Correct 55 ms 41080 KB Output is correct
31 Correct 55 ms 41336 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 37884 KB Output is correct
2 Correct 35 ms 37880 KB Output is correct
3 Correct 34 ms 37880 KB Output is correct
4 Correct 34 ms 38008 KB Output is correct
5 Correct 34 ms 37888 KB Output is correct
6 Correct 35 ms 37880 KB Output is correct
7 Correct 54 ms 37940 KB Output is correct
8 Correct 35 ms 37880 KB Output is correct
9 Correct 34 ms 37880 KB Output is correct
10 Correct 34 ms 37880 KB Output is correct
11 Correct 35 ms 37880 KB Output is correct
12 Correct 34 ms 38008 KB Output is correct
13 Correct 34 ms 38008 KB Output is correct
14 Correct 34 ms 37980 KB Output is correct
15 Correct 33 ms 37888 KB Output is correct
16 Correct 35 ms 38008 KB Output is correct
17 Correct 35 ms 38008 KB Output is correct
18 Correct 35 ms 38008 KB Output is correct
19 Correct 34 ms 38016 KB Output is correct
20 Correct 34 ms 37956 KB Output is correct
21 Correct 35 ms 38008 KB Output is correct
22 Correct 36 ms 37988 KB Output is correct
23 Correct 43 ms 39500 KB Output is correct
24 Correct 45 ms 39504 KB Output is correct
25 Correct 44 ms 39416 KB Output is correct
26 Correct 56 ms 40956 KB Output is correct
27 Correct 57 ms 41080 KB Output is correct
28 Correct 55 ms 41080 KB Output is correct
29 Correct 58 ms 41080 KB Output is correct
30 Correct 55 ms 41080 KB Output is correct
31 Correct 55 ms 41336 KB Output is correct
32 Correct 176 ms 53460 KB Output is correct
33 Correct 168 ms 53368 KB Output is correct
34 Correct 172 ms 53368 KB Output is correct
35 Correct 826 ms 100000 KB Output is correct
36 Correct 824 ms 99832 KB Output is correct
37 Correct 810 ms 99960 KB Output is correct
38 Correct 737 ms 102756 KB Output is correct
39 Correct 771 ms 101396 KB Output is correct
40 Correct 800 ms 102212 KB Output is correct
41 Correct 854 ms 103244 KB Output is correct