oj.uz

Submission #31655

# Submission time Handle Problem Language Result Execution time Memory
31655 2017-08-30T14:09:54 Z minhtung0404 Beads and wires (APIO14_beads) C++14
100 / 100
 453 ms 23028 KB 
#include<bits/stdc++.h>
const int N = 2e5 + 5;
const int inf = 1e9;
using namespace std;

typedef pair <int, int> ii;
vector <ii> adj[N];
int n, f[N][2], g[N][2], p[N], a, b, c, maxxx, co[N], ans[N];
int maxx[N][2], L[N][2], R[N][2];

void dfs(int u){
    int ma = -inf;
    f[u][1] = -inf;
    f[u][0] = 0;
    for(int i = 0; i < adj[u].size(); i++){
        int v = adj[u][i].first;
        if (v == p[u]) continue;
        p[v] = u;
        dfs(v);
    }
    for (int i = 0; i < adj[u].size(); i++){
        int v = adj[u][i].first, cost = adj[u][i].second;
        if (v == p[u]) continue;
        f[u][0] += max(f[v][1]+cost, f[v][0]);
        co[v] = cost;
        if (f[v][1]+cost > f[v][0]) ma = max(ma, f[v][0] - f[v][1]);
        else ma = max(ma, cost);
    }
    f[u][1] = f[u][0] + ma;
}

void DFS(int u){
    int cak = co[u], sz = adj[u].size();
    if (g[u][1] + co[u] > g[u][0]) cak = g[u][0] - g[u][1];
    ans[u] = g[u][0] + f[u][0];

    L[0][0] = 0;
    L[0][1] = -inf;
    maxx[0][0] = -inf;
    for (int i = 0; i < sz; i++){
        int v = adj[u][i].first, cost = adj[u][i].second;
        if (v == p[u]) {
            L[i+1][0] = L[i][0];
            L[i+1][1] = L[i][1];
            maxx[i+1][0] = maxx[i][0];
            continue;
        }
        L[i+1][0] = L[i][0] + max(f[v][0], f[v][1] + cost);

        int z;
        if (f[v][0] > f[v][1] + cost) z = cost;
        else z = f[v][0] - f[v][1];

        maxx[i+1][0] = max(maxx[i][0], z);
        L[i+1][1] = L[i+1][0] + maxx[i+1][0];
    }
    R[sz+1][0] = 0;
    R[sz+1][1] = -inf;
    maxx[sz+1][1] = -inf;
    for (int i = sz-1; i >= 0; i--){
        int v = adj[u][i].first, cost = adj[u][i].second;
        if (v == p[u]) {
            R[i+1][0] = R[i+2][0];
            R[i+1][1] = R[i+2][1];
            maxx[i+1][1] = maxx[i+2][1];
            continue;
        }
        R[i+1][0] = R[i+2][0] + max(f[v][0], f[v][1] + cost);
        int z;
        if (f[v][0] > f[v][1] + cost) z = cost;
        else z = f[v][0] - f[v][1];
        maxx[i+1][1] = max(maxx[i+2][1], z);
        R[i+1][1] = R[i+1][0] + maxx[i+1][1];
    }
    for (int i = 0; i < sz; i++){
        int v = adj[u][i].first, cost = adj[u][i].second;
        if (v == p[u]) continue;
        g[v][0] = max(g[v][0], g[u][0] + L[i][0] + R[i+2][0]);
        g[v][0] = max(g[v][0], g[u][1] + L[i][0] + R[i+2][0] + cost);
        g[v][0] = max(g[v][0], g[u][0] + L[i][1] + R[i+2][0] + cost);
        g[v][0] = max(g[v][0], g[u][0] + L[i][0] + R[i+2][1] + cost);
        g[v][1] = g[u][0] + L[i][0] + R[i+2][0] + cost;
    }

    for (int i = 0; i < sz; i++){
        int v = adj[u][i].first;
        if (v == p[u]) continue;
        DFS(v);
    }
}

int main(){
    cin >> n;
    for (int i = 1; i < n; i++){
        cin >> a >> b >> c;
        adj[a].push_back(ii(b, c));
        adj[b].push_back(ii(a, c));
    }
    dfs(1);
    g[1][1] = -inf;
    DFS(1);
    for (int i = 1; i <= n; i++){
        maxxx = max(maxxx, ans[i]);
    }
    cout << maxxx;
}
/*
5
1 2 10
1 3 40
1 4 15
1 5 20

10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/

Compilation message

beads.cpp: In function 'void dfs(int)':
beads.cpp:15:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < adj[u].size(); i++){
                    ~~^~~~~~~~~~~~~~~
beads.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < adj[u].size(); i++){
                     ~~^~~~~~~~~~~~~~~
beads.cpp: In function 'void DFS(int)':
beads.cpp:33:9: warning: variable 'cak' set but not used [-Wunused-but-set-variable]
     int cak = co[u], sz = adj[u].size();
         ^~~

Subtask #1
13.0 / 13.0

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

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 5 ms 5120 KB Output is correct
5 Correct 5 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 5 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 5120 KB Output is correct
13 Correct 6 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 7 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 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 5 ms 5120 KB Output is correct
5 Correct 5 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 5 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 5120 KB Output is correct
13 Correct 6 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 7 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 10 ms 5376 KB Output is correct
24 Correct 11 ms 5376 KB Output is correct
25 Correct 11 ms 5376 KB Output is correct
26 Correct 17 ms 5760 KB Output is correct
27 Correct 15 ms 5760 KB Output is correct
28 Correct 17 ms 6008 KB Output is correct
29 Correct 17 ms 5888 KB Output is correct
30 Correct 16 ms 5760 KB Output is correct
31 Correct 18 ms 6144 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5120 KB Output is correct
2 Correct 6 ms 5120 KB Output is correct
3 Correct 6 ms 4992 KB Output is correct
4 Correct 5 ms 5120 KB Output is correct
5 Correct 5 ms 5120 KB Output is correct
6 Correct 6 ms 5120 KB Output is correct
7 Correct 5 ms 5120 KB Output is correct
8 Correct 6 ms 5120 KB Output is correct
9 Correct 5 ms 5120 KB Output is correct
10 Correct 6 ms 5120 KB Output is correct
11 Correct 6 ms 5120 KB Output is correct
12 Correct 5 ms 5120 KB Output is correct
13 Correct 6 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 7 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 10 ms 5376 KB Output is correct
24 Correct 11 ms 5376 KB Output is correct
25 Correct 11 ms 5376 KB Output is correct
26 Correct 17 ms 5760 KB Output is correct
27 Correct 15 ms 5760 KB Output is correct
28 Correct 17 ms 6008 KB Output is correct
29 Correct 17 ms 5888 KB Output is correct
30 Correct 16 ms 5760 KB Output is correct
31 Correct 18 ms 6144 KB Output is correct
32 Correct 98 ms 8344 KB Output is correct
33 Correct 74 ms 8344 KB Output is correct
34 Correct 75 ms 8440 KB Output is correct
35 Correct 387 ms 18200 KB Output is correct
36 Correct 390 ms 18036 KB Output is correct
37 Correct 453 ms 18152 KB Output is correct
38 Correct 309 ms 22736 KB Output is correct
39 Correct 305 ms 20436 KB Output is correct
40 Correct 341 ms 19672 KB Output is correct
41 Correct 399 ms 23028 KB Output is correct