Submission #996442

#	Time	Username	Problem	Language	Result	Execution time	Memory
996442		otarius	Designated Cities (JOI19_designated_cities)	C++17	0 / 100	2 ms	7004 KiB

designated_cities

#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <cstring>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>
using namespace std;

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair <int, int>
#define ull unsigned long long

#define int long long
// #define int unsigned long long

const ll inf = 1e9 + 7;
const ll weirdMod = 998244353;

pii rts;
vector<pair<int, pii>> G[200005];
int n, q, val[200005], ans[200005], dep[200005], dp[200005], mx;
bool comp(int a, int b) {
    return (val[a] + dep[a] > val[b] + dep[b]);
}
void temp_dfs(int v, int par) {
    for (auto u : G[v]) {
        if (u.ff == par) continue;
        val[1] += u.sc.sc;
        dep[u.ff] = dep[v] + u.sc.ff;
        temp_dfs(u.ff, v);
    }
}
void reroot_dfs(int v, int par) {
    for (auto u : G[v]) {
        if (u.ff == par) continue;
        val[u.ff] = val[v] - u.sc.sc + u.sc.ff;
        reroot_dfs(u.ff, v);
    }
}
void pair_dfs(int v, int par) {
    vector<int> vec = {v};
    for (auto u : G[v]) {
        if (u.ff == par) continue;
        pair_dfs(u.ff, v); vec.pb({dp[u.ff]});
    } sort(vec.begin(), vec.end(), comp);
    dp[v] = vec[0];
    if (vec.size() == 1) return;
    int cur = val[vec[0]] + val[vec[1]] + dep[vec[0]] + dep[vec[1]] - 2 * dep[v];
    if (cur > mx) {
        mx = cur; rts = {vec[0], vec[1]};
    }
}
void solve() {
    cin >> n;
    int sum = 0;
    for (int i = 1; i < n; i++) {
        int a, b, x, y;
        cin >> a >> b >> x >> y;
        G[a].pb({b, {x, y}});
        G[b].pb({a, {y, x}});
        sum += x + y;
    } temp_dfs(1, 0); reroot_dfs(1, 0); pair_dfs(1, 0);
    mx /= 2;
    cout << sum - mx;
}
int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
        cout << '\n';
    }
    return 0;
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 7
• Subtask 3: 0 / 9
• Subtask 4: 0 / 17
• Subtask 5: 0 / 17
• Subtask 6: 0 / 44