Submission #1261361

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261361		tvgk	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	271 ms	30880 KiB

election_campaign

#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define se second
#define fi first
#define ll long long
#define ii pair<int, int>
#define tp tuple<int, int, int>
const long mxN = 1e5 + 7;

int n, h[mxN], in[mxN], out[mxN], par[mxN][25], tree[mxN * 4], dp[mxN][2], num;
vector<int> w[mxN];
vector<tp> querry[mxN];

void Build(int j)
{
    in[j] = ++num;
    h[j] = h[par[j][0]] + 1;
    for (int i = 1; i <= 19; i++)
        par[j][i] = par[par[j][i - 1]][i - 1];

    for (int i : w[j])
    {
        if (h[i])
            continue;

        par[i][0] = j;
        Build(i);
    }
    out[j] = num;
}

int LCA(int u, int v)
{
    if (h[u] < h[v])
        swap(u, v);

    for (int i = 19; i >= 0; i--)
    {
        if (h[par[u][i]] >= h[v])
            u = par[u][i];
    }

    if (u == v)
        return u;

    for (int i = 19; i >= 0; i--)
    {
        if (par[u][i] != par[v][i])
        {
            u = par[u][i];
            v = par[v][i];
        }
    }
    return par[u][0];
}

int Get(int vt, int j = 1, int l = 1, int r = n)
{
    if (l > vt || vt > r)
        return 0;

    if (l == r)
        return tree[j];

    int mid = (l + r) / 2;
    return Get(vt, j * 2, l, mid) + Get(vt, j * 2 + 1, mid + 1, r) + tree[j];
}

void Upd(int u, int v, int val, int j = 1, int l = 1, int r = n)
{
    if (u > r || l > v)
        return;

    if (u <= l && r <= v)
    {
        tree[j] += val;
        return;
    }

    int mid = (l + r) / 2;
    Upd(u, v, val, j * 2, l, mid);
    Upd(u, v, val, j * 2 + 1, mid + 1, r);
}

void DFS(int j)
{
    for (int i : w[j])
    {
        if (i == par[j][0])
            continue;

        DFS(i);
        dp[j][0] += dp[i][1];
    }

    dp[j][1] = dp[j][0];
    for (auto [u, v, val] : querry[j])
        dp[j][1] = max(dp[j][1], dp[j][0] + Get(in[u]) + Get(in[v]) + val);
    Upd(in[j], out[j], dp[j][0] - dp[j][1]);
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    //freopen(task".INP", "r", stdin);
    //freopen(task".OUT", "w", stdout);

    cin >> n;
    for (int i = 1; i < n; i++)
    {
        int u, v;
        cin >> u >> v;
        w[u].push_back(v);
        w[v].push_back(u);
    }
    Build(1);

    int q;
    cin >> q;
    for (int i = 1; i <= q; i++)
    {
        int u, v, val;
        cin >> u >> v >> val;
        int root = LCA(u, v);
        querry[root].push_back({u, v, val});
    }
    DFS(1);

    cout << dp[1][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