Submission #1189462

#	Time	Username	Problem	Language	Result	Execution time	Memory
1189462		onbert	Designated Cities (JOI19_designated_cities)	C++20	23 / 100	2095 ms	27756 KiB

designated_cities

#include <bits/stdc++.h>
using namespace std;
#define int long long
struct edge {
    int v, c, d;
    bool operator == (const edge &b) const {
        return (v == b.v && c == b.c && d == b.d);
    }
};

const int maxn = 2e5 + 5;
int n;
vector<edge> adj[maxn];
int ans[maxn];

int curans1 = 0, add1 = 0;
void dfs1(int u, int f) {
    ans[1] = max(curans1, ans[1]);
    for (auto [v, c, d]:adj[u]) if (v != f) {
        add1 += d;
        curans1 -= d, curans1 += c;
        dfs1(v, u);
        curans1 += d, curans1 -= c;
    }
}

int N, cent;
int sz[maxn];
vector<int> nodes;

void init(int u, int f) {
    N++;
    nodes.push_back(u);
    for (auto [v, c, d]:adj[u]) if (v != f) init(v, u);
}

void find_cent(int u, int f) {
    sz[u] = 1;
    bool can = true;
    for (auto [v, c, d]:adj[u]) if (v != f) {
        find_cent(v, u);
        sz[u] += sz[v];
        if (sz[v] > N/2) can = false;
    }
    if (N - sz[u] > N/2) can = false;
    if (can) cent = u;
}

int cost[maxn], up[maxn], fa[maxn], dir[maxn];
void dfscost(int u, int f) {
    up[u] = 0;
    for (auto [v, c, d]:adj[u]) if (v != f) {
        fa[v] = u, dir[v] = c;
        cost[v] = cost[u] + c;
        dfscost(v, u);
        up[u] += up[v] + d;
    }
}

int curans;

pair<int,int> Emx(int u) {
    pair<int,int> val = {cost[u], u};
    for (auto [v, c, d]:adj[u]) if (v != fa[u]) {
        val = max(Emx(v), val);
    }
    return val;
}

void Eupdate(int u, int val) {
    cost[u] += val;
    for (auto [v, c, d]:adj[u]) if (v != fa[u]) Eupdate(v, val);
}

void update(int u) {
    while (cost[u]) {
        Eupdate(u, -dir[u]);
        curans += dir[u];
        u = fa[u];
    }
}

void solve(int start, int add) {
    N = 0;
    nodes.clear();
    init(start, 0);
    // cout << "start " << start << endl;
    find_cent(start, 0);
    // cout << N << " " << endl;
    // for (int i:nodes) cout << i << " "; cout << endl;
    if (N == 2) ans[2] = max(adj[nodes[0]][0].c + adj[nodes[0]][0].d + add, ans[2]);
    if (N <= 2) return;

    // cout << cent << endl;
    cost[cent] = 0;
    dfscost(cent, 0);
    add += up[cent];
    curans = 0;
    vector<pair<int,int>> vec;
    for (auto [v, c, d]:adj[cent]) vec.push_back(Emx(v));
    sort(vec.rbegin(), vec.rend());
    update(vec[0].second); update(vec[1].second);
    ans[2] = max(curans + add, ans[2]);
    // cout << "TEST\n";
    // cout << cent << endl;
    // for (int i:nodes) cout << i << " "; cout << endl;
    // cout << curans + add << endl;
    for (int i=3;i<=N;i++) {
        int guy = Emx(cent).second;
        update(guy);
        ans[i] = max(curans + add, ans[i]);
    }

    int thiscent = cent;
    for (auto [v, c, d]:adj[thiscent]) {
        edge del = {thiscent, d, c};
        adj[v].erase(find(adj[v].begin(), adj[v].end(), del));
        // cout << "nxt: " << thiscent << " " << v << endl;
        solve(v, add - up[v] - d + c);
        // cout << "done: " << cent << " " << v << endl;
    }

}


signed main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n;
    int all = 0;
    for (int i=1;i<=n-1;i++) {
        int u, v, c, d;
        cin >> u >> v >> c >> d;
        adj[u].push_back({v, c, d});
        adj[v].push_back({u, d, c});
        all += c + d;
    }
    dfs1(1, 0);
    ans[1] += add1;

    solve(1, 0);

    int q;
    cin >> q;
    while (q--) {
        int x;
        cin >> x;
        cout << all - ans[x] << "\n";
    }
}

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