Submission #746797

#	Time	Username	Problem	Language	Result	Execution time	Memory
746797		GrindMachine	Election Campaign (JOI15_election_campaign)	C++17	20 / 100	1080 ms	43424 KiB

election_campaign

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<ll> adj[N];

struct lca_algo {
    // LCA template (for graphs with 1-based indexing)

    int LOG = 1;
    vector<int> depth;
    vector<vector<int>> up;

    lca_algo() {

    }

    lca_algo(int n) {
        lca_init(n);
    }

    void lca_init(int n) {
        while ((1 << LOG) < n) LOG++;
        up = vector<vector<int>>(n + 1, vector<int>(LOG, 1));
        depth = vector<int>(n + 1);

        lca_dfs(1, -1);
    }

    void lca_dfs(int node, int par) {
        trav(child, adj[node]) {
            if (child == par) conts;

            up[child][0] = node;
            rep1(j, LOG - 1) {
                up[child][j] = up[up[child][j - 1]][j - 1];
            }

            depth[child] = depth[node] + 1;

            lca_dfs(child, node);
        }
    }

    int lift(int u, int k) {
        rep(j, LOG) {
            if (k & (1 << j)) {
                u = up[u][j];
            }
        }

        return u;
    }

    int query(int u, int v) {
        if (depth[u] < depth[v]) swap(u, v);
        int k = depth[u] - depth[v];
        u = lift(u, k);

        if (u == v) return u;

        rev(j, LOG - 1, 0) {
            if (up[u][j] != up[v][j]) {
                u = up[u][j];
                v = up[v][j];
            }
        }

        u = up[u][0];
        return u;
    }

    int get_dis(int u, int v) {
        int lca = query(u, v);
        return depth[u] + depth[v] - 2 * depth[lca];
    }
};

vector<array<ll,3>> here[N];
vector<ll> dp(N);
vector<ll> tin(N), tout(N);
vector<ll> par(N,-1);
ll timer = 1;
ll n;

void dfs1(ll u, ll p){
    tin[u] = timer++;
    trav(v, adj[u]){
        if(v == p) conts;
        par[v] = u;
        dfs1(v, u);
    }
    tout[u] = timer++;
}

void dfs2(ll u, ll p){
    trav(v, adj[u]){
        if(v == p) conts;
        dfs2(v, u);
    }

    // pick 1 path passing through u
    for(auto [x, y, w] : here[u]){
        ll val = w;

        rep1(i,n){
            if(i == u) conts;
            if(tin[u] <= tin[i] and tout[u] >= tout[i]){
                if(tin[i] <= tin[x] and tout[i] >= tout[x]) conts;
                if(tin[i] <= tin[y] and tout[i] >= tout[y]) conts;

                ll pa = par[i];
                if((tin[pa] <= tin[x] and tout[pa] >= tout[x]) or (tin[pa] <= tin[y] and tout[pa] >= tout[y])){
                    val += dp[i];
                }
            }
        }

        amax(dp[u], val);
    }

    // dont pick any path going through u
    ll sum = 0;

    trav(v,adj[u]){
        if(v == p) conts;
        sum += dp[v];
    }

    amax(dp[u], sum);
}

void solve(int test_case)
{
    cin >> n;
    rep1(i,n-1){
        ll u,v; cin >> u >> v;
        adj[u].pb(v), adj[v].pb(u);
    }

    lca_algo LCA(n);

    ll m; cin >> m;

    rep1(i,m){
        ll u,v,w; cin >> u >> v >> w;
        ll lca = LCA.query(u,v);
        here[lca].pb({u, v, w});
    }

    dfs1(1, -1);
    dfs2(1, -1);

    ll ans = dp[1];
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 5
• Subtask 3: 0 / 5
• Subtask 4: 0 / 30
• Subtask 5: 10 / 10
• Subtask 6: 0 / 40