Submission #1125491

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125491		adaawf	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	308 ms	84872 KiB

election_campaign

#include <iostream>
#include <vector>
#include <unordered_map>
using namespace std;
vector<int> g[100005], vv[100005], v[100005];
long long int l[100005][18], d[100005], f[100005], n, c[100005], dd[100005];
unordered_map<int, long long int> s[100005];
void dfs(int x, int p) {
    l[x][0] = p;
    for (int w : g[x]) {
        if (w == p) continue;
        d[w] = d[x] + 1;
        dfs(w, x);
    }
}
int lca(int x, int y) {
    if (d[x] < d[y]) swap(x, y);
    int k = d[x] - d[y];
    for (int i = 17; i >= 0; i--) {
        if (k & (1 << i)) {
            x = l[x][i];
        }
    }
    if (x == y) return x;
    for (int i = 17; i >= 0; i--) {
        if (l[x][i] != l[y][i]) {
            x = l[x][i];
            y = l[y][i];
        }
    }
    return l[x][0];
}
void dfs2(int x, int p) {
    long long int res = 0;
    for (int w : g[x]) {
        if (w == p) continue;
        dfs2(w, x);
        res += f[w];
    }
    f[x] = max(f[x], res);
    for (int w : vv[x]) s[x][w] = 0;
    for (int w : g[x]) {
        if (w == p) continue;
        if (s[x].size() < s[w].size()) {
            s[x].swap(s[w]);
            swap(dd[x], dd[w]);
        }
        for (auto v : s[w]) {
            long long int h = v.second + dd[w];
            if (s[x].count(v.first)) s[x][v.first] += h;
            else s[x][v.first] += h - dd[x];
        }
    }
    dd[x] += f[x];
    for (int w : v[x]) {
        f[x] = max(f[x], s[x][w] + dd[x] + c[w]);
    }
    dd[x] -= f[x];
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin >> n;
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dfs(1, 0);
    for (int i = 1; i <= 17; i++) {
        for (int j = 1; j <= n; j++) {
            l[j][i] = l[l[j][i - 1]][i - 1];
        }
    }
    int m;
    cin >> m;
    for (int i = 1; i <= m; i++) {
        int x, y;
        cin >> x >> y >> c[i];
        v[lca(x, y)].push_back(i);
        vv[x].push_back(i);
        vv[y].push_back(i);
    }
    dfs2(1, -1);
    cout << f[1];
}

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40