Submission #958031

#	Time	Username	Problem	Language	Result	Execution time	Memory
958031		starchan	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	130 ms	28476 KiB

election_campaign

#include<bits/stdc++.h>
using namespace std;
#define in pair<int, int>
#define inn pair<int, in>
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int MX = 1e5+5, LOGM = 18;
vector<int> adj[MX];
vector<inn> st[MX];
int tin[MX], tout[MX], pa[LOGM][MX], dp[MX];

int timer;
void dfs(int u, int p)
{
	tin[u] = ++timer;
	pa[0][u] = p;
	for(int v: adj[u])
	{
		if(v==p)
			continue;
		dfs(v, u);
	}
	tout[u] = timer;
	return;
}

int lca(int u, int v)
{
	if(tin[u] >= tin[v])
		swap(u, v);
	if(tout[u] >= tout[v])
		return u;
	for(int i = LOGM-1; i >= 0; i--)
	{
		int k = pa[i][u];
		if(tout[k] >= tout[v])
			continue;
		u = k;
	}
	return pa[0][u];
}

int fen[MX];
void add(int x, int val)
{
	for(; x < MX; x+=(x&-x))
		fen[x]+=val;
	return;
}
int Q(int u)
{
	int ret = 0;
	for(int x = tin[u]; x; x-=(x&-x))
		ret+=fen[x];
	return ret;
}
void upd(int val, int u)
{
	add(tin[u], val);
	add(tout[u]+1, -val);
	return;
}


void DFS(int u, int p)
{
	int SUM = 0;
	for(int v: adj[u])
	{
		if(v == p)
			continue;
		DFS(v, u);
		SUM+=dp[v]; 
	}
	for(auto [C, ab]: st[u])
		dp[u] = max(dp[u], C+Q(ab.f)+Q(ab.s));
	dp[u]+=SUM;
	upd(SUM-dp[u], u);
	return;
}

signed main()
{
	fast();
	int n;
	cin >> n;
	int m = n-1;
	while(m--)
	{
		int u, v;
		cin >> u >> v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	pa[0][0] = 0; tin[0] = -1; tout[0] = INF;
	dfs(1, 0);
	for(int j = 1; j < LOGM; j++)
	{
		for(int i = 0; i <= n; i++)
			pa[j][i] = pa[j-1][pa[j-1][i]];
	}
	int q; cin >> q;
	while(q--)
	{
		int l, r, w;
		cin >> l >> r >> w;
		st[lca(l, r)].pb({w, {l, r}});
	}
	DFS(1, 0);
	cout << dp[1] << "\n";
	return 0;
}	

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