Submission #1125159

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125159		elush	Designated Cities (JOI19_designated_cities)	C++20	100 / 100	1376 ms	38308 KiB

designated_cities

#include <bits/stdc++.h>
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define chkmax(a, b) a = max(a, b)
#define chkmin(a, b) a = min(a, b)
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pii;
typedef vector<pii> vii;

const int MAX_N = 2e5 + 5;

ll ans[MAX_N];
bool visited[MAX_N];
int sz[MAX_N];

vii tree[MAX_N];

int DfsSz(int node, int par) {
    sz[node] = 1;
    for (auto [neighbor, w] : tree[node]) {
        if (neighbor != par && !visited[neighbor]) sz[node] += DfsSz(neighbor, node);
    }
    return sz[node];
}

int FindCentroid(int node) {
    DfsSz(node, node);
    int s = sz[node];
    int par = node;
    while (true) {
        bool ok = true;
        for (auto [neighbor, w] : tree[node]) {
            if (!visited[neighbor] && neighbor != par && sz[neighbor] >= s / 2) {
                par = node;
                node = neighbor;
                ok = false;
                break;
            }
        }
        if (ok) break;
    }
    return node;
}

vii options;

ll Solve(int node, int par, ll d, int ind) {
    vi v = {0};
    for (auto [neighbor, w] : tree[node]) {
        if (neighbor != par && !visited[neighbor]) {
            v.push_back(Solve(neighbor, node, w, ind));
        }
    }
    int i = max_element(all(v)) - v.begin();
    swap(v[0], v[i]);
    for (int j = 1; j < v.size(); j++) {
        options.push_back({v[j], ind});
    }
    return v[0] + d;
}

ll CalcBonus(int node, int par) {
    ll s = 0;
    for (auto [neighbor, w] : tree[node]) {
        if (neighbor == par) s += w;
        else if (!visited[neighbor]) s += CalcBonus(neighbor, node);
    }
    return s;
}

void CentroidDecomposition(int node, ll bonus) {
    int centroid = FindCentroid(node);
    options.clear();
    for (auto [node, w] : tree[centroid]) {
        if (!visited[node]) {
            options.push_back({Solve(node, centroid, w, node), node});
        }
    }
    options.push_back({0, centroid});
    ll curr = CalcBonus(centroid, centroid) + bonus;
    sort(all(options), greater<pii>());
    chkmax(ans[1], curr);
    if (options.size() == 1) return;
    ll s = curr + options[0].x;
    int i = 1;
    while (options[i].y == options[0].y) i++;
    s += options[i].x;
    chkmax(ans[2], s);
    for (int j = 1, c = 2; j < options.size(); j++) {
        if (j != i) c++, s += options[j].x;
        chkmax(ans[c], s);
    }
    visited[centroid] = true;
    for (auto [node, w] : tree[centroid]) {
        if (!visited[node]) {
            CentroidDecomposition(node, curr + w - CalcBonus(node, centroid));
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    ll s = 0;
    for (int i = 0; i < n - 1; i++) {
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        s += c + d;
        tree[a].push_back({b, c});
        tree[b].push_back({a, d});
    }
    CentroidDecomposition(1, 0);
    int q;
    cin >> q;
    while (q--) {
        int e;
        cin >> e;
        cout << s - ans[e] << '\n';
    }
}

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