oj.uz

Submission #135175

# Submission time Handle Problem Language Result Execution time Memory
135175 2019-07-23T18:12:47 Z fredbr Beads and wires (APIO14_beads) C++17
28 / 100
 1000 ms 1276 KB 
#include <bits/stdc++.h>
 
#pragma GCC optimize("O3")
 
using namespace std;
 
int const maxn = 10001;
 
struct Edge {
    int u, w;
};
 
vector<Edge> v[maxn];
int n;
int dp[2][maxn];
 
inline int invalid(int x) {
    return v[x].size() == 1;
}
 
int solve(int x, int p = -1, int t = 0) {
    if (dp[x][t] >= 0) return dp[x][t];
 
    int d = 0;
 
    if (t == 0) {
        for (Edge const& e : v[x]) {
            if (e.u == p) continue;
 
            if (!invalid(e.u)) {
                d += max(solve(e.u, x, 1) + e.w, solve(e.u, x, 0));
            }
        }
    }
    else {
        int sum = solve(x, p, 0);
 
        for (Edge const& e : v[x]) {
            if (e.u == p) continue;
 
            if (!invalid(e.u))
                d = max(d, sum - max(solve(e.u, x, 1) + e.w, solve(e.u, x, 0))
                           + e.w + solve(e.u, x, 0));
            else
                d = max(d, sum + e.w);
        }
    }
 
    return dp[x][t] = d;
}

char vis[maxn];
int res[maxn];

void bfs_order(int ini) {
    queue<int> q {{ini}};
    vis[ini] = 1;

    int at = 0;
    while (!q.empty()) {
        int x = q.front();
        res[at++] = x;
        q.pop();

        for (Edge const& e : v[x]) {
            if (vis[e.u]) continue;
            vis[e.u] = 1;
            q.push(e.u);
        }
    }
}


inline int test(int ini) {
    memset(vis, 0, sizeof(vis));
    bfs_order(ini);

    memset(vis, 0, sizeof(vis));

    for (int i = n-1; i >= 0; i--) {
        int x = res[i];
        vis[x] = 1;

        if (v[x].size() == 1 and x != ini) {
            dp[0][x] = 0, dp[1][x] = 0;
            continue;
        }

        int d = 0;
     
        for (Edge const& e : v[x]) {
            if (!vis[e.u]) continue;
 
            if (!invalid(e.u)) {
                d += max(dp[1][e.u] + e.w, dp[0][e.u]);
            }
        }
        dp[0][x] = d;

        d = 0;
        int sum = dp[0][x];
     
        for (Edge const& e : v[x]) {
            if (!vis[e.u]) continue;
 
            if (!invalid(e.u))
                d = max(d, sum - max(dp[1][e.u] + e.w, dp[0][e.u])
                           + e.w + dp[0][e.u]);
            else
                d = max(d, sum + e.w);
        }

        dp[1][x] = d;
    }

    return dp[0][ini];
}
 
int main() {
    ios::sync_with_stdio(false), cin.tie(nullptr);
 
    cin >> n;
 
    for (int i = 0; i < n-1; i++) {
        int a, b, w;
        cin >> a >> b >> w;
 
        v[a].push_back({b, w});
        v[b].push_back({a, w});
    }
 
    int ans = 0;
    for (int i = 1; i <= n; i++)
        if (v[i].size() == 1)
            ans = max(ans, test(i));
 
    cout << ans << "\n";
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 636 KB Output is correct
3 Correct 2 ms 632 KB Output is correct
4 Correct 2 ms 632 KB Output is correct
5 Correct 2 ms 632 KB Output is correct
6 Correct 2 ms 632 KB Output is correct
7 Correct 2 ms 632 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 636 KB Output is correct
10 Correct 2 ms 632 KB Output is correct
11 Correct 2 ms 632 KB Output is correct
12 Correct 2 ms 632 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 636 KB Output is correct
3 Correct 2 ms 632 KB Output is correct
4 Correct 2 ms 632 KB Output is correct
5 Correct 2 ms 632 KB Output is correct
6 Correct 2 ms 632 KB Output is correct
7 Correct 2 ms 632 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 636 KB Output is correct
10 Correct 2 ms 632 KB Output is correct
11 Correct 2 ms 632 KB Output is correct
12 Correct 2 ms 632 KB Output is correct
13 Correct 2 ms 632 KB Output is correct
14 Correct 2 ms 632 KB Output is correct
15 Correct 2 ms 632 KB Output is correct
16 Correct 3 ms 632 KB Output is correct
17 Correct 3 ms 632 KB Output is correct
18 Correct 3 ms 632 KB Output is correct
19 Correct 3 ms 632 KB Output is correct
20 Correct 3 ms 632 KB Output is correct
21 Correct 3 ms 636 KB Output is correct
22 Correct 3 ms 632 KB Output is correct

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 636 KB Output is correct
3 Correct 2 ms 632 KB Output is correct
4 Correct 2 ms 632 KB Output is correct
5 Correct 2 ms 632 KB Output is correct
6 Correct 2 ms 632 KB Output is correct
7 Correct 2 ms 632 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 636 KB Output is correct
10 Correct 2 ms 632 KB Output is correct
11 Correct 2 ms 632 KB Output is correct
12 Correct 2 ms 632 KB Output is correct
13 Correct 2 ms 632 KB Output is correct
14 Correct 2 ms 632 KB Output is correct
15 Correct 2 ms 632 KB Output is correct
16 Correct 3 ms 632 KB Output is correct
17 Correct 3 ms 632 KB Output is correct
18 Correct 3 ms 632 KB Output is correct
19 Correct 3 ms 632 KB Output is correct
20 Correct 3 ms 632 KB Output is correct
21 Correct 3 ms 636 KB Output is correct
22 Correct 3 ms 632 KB Output is correct
23 Correct 917 ms 1016 KB Output is correct
24 Correct 951 ms 964 KB Output is correct
25 Correct 912 ms 960 KB Output is correct
26 Execution timed out 1054 ms 1276 KB Time limit exceeded
27 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 632 KB Output is correct
2 Correct 2 ms 636 KB Output is correct
3 Correct 2 ms 632 KB Output is correct
4 Correct 2 ms 632 KB Output is correct
5 Correct 2 ms 632 KB Output is correct
6 Correct 2 ms 632 KB Output is correct
7 Correct 2 ms 632 KB Output is correct
8 Correct 2 ms 632 KB Output is correct
9 Correct 2 ms 636 KB Output is correct
10 Correct 2 ms 632 KB Output is correct
11 Correct 2 ms 632 KB Output is correct
12 Correct 2 ms 632 KB Output is correct
13 Correct 2 ms 632 KB Output is correct
14 Correct 2 ms 632 KB Output is correct
15 Correct 2 ms 632 KB Output is correct
16 Correct 3 ms 632 KB Output is correct
17 Correct 3 ms 632 KB Output is correct
18 Correct 3 ms 632 KB Output is correct
19 Correct 3 ms 632 KB Output is correct
20 Correct 3 ms 632 KB Output is correct
21 Correct 3 ms 636 KB Output is correct
22 Correct 3 ms 632 KB Output is correct
23 Correct 917 ms 1016 KB Output is correct
24 Correct 951 ms 964 KB Output is correct
25 Correct 912 ms 960 KB Output is correct
26 Execution timed out 1054 ms 1276 KB Time limit exceeded
27 Halted 0 ms 0 KB -