oj.uz

Submission #249115

# Submission time Handle Problem Language Result Execution time Memory
249115 2020-07-14T11:04:44 Z receed Beads and wires (APIO14_beads) C++14
0 / 100
 3 ms 5120 KB 
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <cassert>
#include <string>
#include <set>
#include <map>
#include <random>
#include <bitset>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <queue>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

using namespace std;
using ll = long long;
using ul = unsigned long long;
using ld = long double;

const int N = 200001;
vector<pair<int, int>> g[N];
ll d0[N], d1[N], d2[N], d3[N], pw[N], inf = 1e11;


void dfs(int v, int p) {
    ll t1 = -inf, t2 = -inf, t3 = -inf, w0 = -inf, w2 = -inf, z2 = -inf;
    for (auto &e : g[v]) {
        int u = e.first;
        if (u == p)
            continue;
        dfs(u, v);
        pw[u] = e.second;
        d1[u] += e.second; d3[u] += e.second;
        d1[u] = max(d1[u], d0[u]);
        d2[u] = max(d2[u], d0[u]);
        d3[u] = max(d3[u], d2[u]);
        // d3[u] = max(d3[u], d1[u]);
        d0[v] += d1[u];
        t1 = max(t1, d0[u] - d1[u] + pw[u]);
        t2 = max(t2, d3[u] - d1[u]);
        t3 = max(t3, d2[u] - d1[u] + pw[u]);
        d2[v] = max(d2[v], w0 + d2[u] + pw[u] - d1[u]);
        d2[v] = max(d2[v], w2 + d0[u] + pw[u] - d1[u]);
        // d3[v] = max(d3[v], w0 + d2[u] - d1[u]);
        // d3[v] = max(d3[v], z2 + d0[u] + pw[u] - d1[u]);
        w0 = max(w0, d0[u] + pw[u] - d1[u]);
        w2 = max(w2, d2[u] + pw[u] - d1[u]);
        // z2 = max(z2, d2[u] - d1[u]);
    }
    d1[v] = d0[v] + t1;
    d2[v] = d0[v] + max(d2[v], t2);
    d3[v] = d0[v] + max(d3[v], t3);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    int n, u, v, w;
    cin >> n;
    rep(i, n - 1) {
        cin >> u >> v >> w;
        u--; v--;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    dfs(0, -1);
    cout << max(d0[0], d2[0]);
}

Compilation message

beads.cpp: In function 'void dfs(int, int)':
beads.cpp:34:63: warning: unused variable 'z2' [-Wunused-variable]
     ll t1 = -inf, t2 = -inf, t3 = -inf, w0 = -inf, w2 = -inf, z2 = -inf;
                                                               ^~

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Incorrect 3 ms 5120 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Incorrect 3 ms 5120 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Incorrect 3 ms 5120 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Incorrect 3 ms 5120 KB Output isn't correct
3 Halted 0 ms 0 KB -