Submission #670495

#	Time	Username	Problem	Language	Result	Execution time	Memory
670495		ghostwriter	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	154 ms	29672 KiB

election_campaign

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
#define FOR(i, l, r) for (int i = (l); i <= (r); ++i)
#define FOS(i, r, l) for (int i = (r); i >= (l); --i)
#define FRN(i, n) for (int i = 0; i < (n); ++i)
#define FSN(i, n) for (int i = (n) - 1; i >= 0; --i)
#define EACH(i, x) for (auto &i : (x))
#define WHILE while
template<typename T> T gcd(T a, T b) { WHILE(b) { a = a % b; swap(a, b); } return a; }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    GOAT
----------------------------------------------------------------
*/
struct Plan {
	int a, b, c;
	Plan() {}
	Plan(int a, int b, int c) : a(a), b(b), c(c) {}
};
const int N = 1e5 + 5;
int n, m, h[N], tin[N], s[N], p[N][17], d[N], f[N], timer = 0;
vi adj[N], d1[N];
Plan P[N];
void input() {
	cin >> n;
	FOR(i, 1, n - 1) {
		int u, v;
		cin >> u >> v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	cin >> m;
	FOR(i, 1, m) cin >> P[i].a >> P[i].b >> P[i].c;
}
void dfs(int u, int p1) {
	tin[u] = ++timer;
	s[u] = 1;
	p[u][0] = p1;
	if (p1) FOR(i, 1, 16) p[u][i] = p[p[u][i - 1]][i - 1];
	EACH(v, adj[u]) {
		if (v == p1) continue;
		h[v] = h[u] + 1;
		dfs(v, u);
		s[u] += s[v];
	}
}
int lca(int a, int b) {
	if (h[a] > h[b]) swap(a, b);
	int diff = h[b] - h[a];
	FRN(i, 17)
		if (diff & (1 << i))
			b = p[b][i];
	if (a == b) return a;
	FSN(i, 17)
		if (p[a][i] != p[b][i]) {
			a = p[a][i];
			b = p[b][i];
		}
	return p[a][0];
}
int getn(int a, int h) { FSN(i, 17) if (h & (1 << i)) a = p[a][i]; return a; }
void upd(int pos, int v) { for (int i = pos; i <= n; i += (i & -i)) f[i] += v; }
void upd(int l, int r, int v) { upd(l, v); upd(r + 1, -v); }
int get(int pos) { int rs = 0; for (int i = pos; i > 0; i -= (i & -i)) rs += f[i]; return rs; }
void dfs1(int u, int p1) {
	int sum = 0;
	EACH(v, adj[u]) {
		if (v == p1) continue;
		dfs1(v, u);
		sum += d[v];
	}
	d[u] = sum;
	EACH(i, d1[u]) {
		int a = P[i].a, b = P[i].b, c = P[i].c;
		d[u] = max(d[u], get(tin[a]) + get(tin[b]) + sum + c);
	}
	upd(tin[u], tin[u] + s[u] - 1, sum - d[u]);
}
void solve() {
	dfs(1, 0);
	FOR(i, 1, m) d1[lca(P[i].a, P[i].b)].pb(i);
	dfs1(1, 0);
	cout << d[1];
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    input();
    solve();
    return 0;
}
/*
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

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