Submission #103631

#	Time	Username	Problem	Language	Result	Execution time	Memory
103631		luciocf	Election Campaign (JOI15_election_campaign)	C++14	0 / 100	601 ms	14740 KiB

election_campaign

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5+10;

int n, m;

int A[maxn], B[maxn], C[maxn];

int nivel[maxn], pai[maxn], sz[maxn];

int chain[maxn], head[maxn], pos[maxn];
int cc, pp;

int tree[4*maxn], lazy[4*maxn];

int dp[maxn];

vector<int> grafo[maxn], op[maxn];

void flush(int node, int l, int r)
{
	if (lazy[node] == -1) return;

	if (l != r)
		lazy[2*node] = lazy[2*node+1] = lazy[node];

	tree[node] = (r-l+1)*lazy[node];
}

void upd(int node, int l, int r, int a, int b, int v)
{
	flush(node, l, r);
	if (l > b || r < a) return;

	if (l >= a && r <= b)
	{
		lazy[node] = v;
		flush(node, l, r);
		return;
	}

	int mid = (l+r)>>1;

	upd(2*node, l, mid, a, b, v); upd(2*node+1, mid+1, r, a, b, v);
}

int soma(int node, int l, int r, int a, int b)
{
	if (a > b) return 0;

	flush(node, l, r);
	if (l > b || r < a) return 0;
	if (l >= a && r <= b) return tree[node];

	int mid = (l+r)>>1;

	return soma(2*node, l, mid, a, b)+soma(2*node+1, mid+1, r, a, b);
}

void dfs(int u, int p)
{
	sz[u] = 1;

	for (auto v: grafo[u])
	{
		if (v == p) continue;

		pai[v] = u, nivel[v] = nivel[u]+1;

		dfs(v, u);

		sz[u] += sz[v];
	}
}

void hld(int u)
{
	if (!head[cc]) head[cc] = u;
	chain[u] = cc, pos[u] = ++pp;

	int maior = -1, ind = -1;
	for (auto v: grafo[u])
		if (v != pai[u] && sz[v] > maior)
			maior = sz[v], ind = v;

	if (ind != -1) hld(ind);

	for (auto v: grafo[u])
		if (v != pai[u] && v != ind)
			cc++, hld(v);
}

int lca(int u, int v)
{
	while (chain[u] != chain[v])
	{
		if (nivel[head[chain[u]]] > nivel[head[chain[v]]])
			u = pai[head[chain[u]]];
		else
			v = pai[head[chain[v]]];
	}

	if (nivel[u] > nivel[v]) return v;
	return u;
}

int query(int u, int v)
{
	int ans = 0;

	while (true)
	{
		if (chain[u] == chain[v])
			return ans+soma(1, 1, n, pos[v], pos[u]);

		ans += soma(1, 1, n, pos[head[chain[u]]], pos[u]);
		u = pai[head[chain[u]]];
	}
}

int solve(int u, int p)
{
	int ans = 0;
	for (auto v: grafo[u])
	{
		if (v == p) continue;

		solve(v, u);

		ans += dp[v];
	}

	dp[u] = ans;

	for (auto i: op[u])
	{
		int a = A[i], b = B[i];
		int x = query(a, u) + query(b, u);

		if (x == 0)
		{
			dp[u] = ans+1;
			upd(1, 1, n, pos[u], pos[u], 1);
		}
	}
}

int main(void)
{
	memset(lazy, -1, sizeof lazy);

	scanf("%d", &n);

	for (int i = 1; i < n; i++)
	{
		int u, v;
		scanf("%d %d", &u, &v);

		grafo[u].push_back(v); grafo[v].push_back(u);
	}

	dfs(1, 0);
	hld(1);

	scanf("%d", &m);

	for (int i = 1; i <= m; i++)
	{
		scanf("%d %d %d", &A[i], &B[i], &C[i]);

		op[lca(A[i], B[i])].push_back(i);
	}

	solve(1, 0);

	printf("%d\n", dp[1]);
}

Compilation message (stderr)

election_campaign.cpp: In function 'int solve(int, int)':
election_campaign.cpp:148:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
election_campaign.cpp: In function 'int main()':
election_campaign.cpp:154:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
election_campaign.cpp:159:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~
election_campaign.cpp:167:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &m);
  ~~~~~^~~~~~~~~~
election_campaign.cpp:171:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &A[i], &B[i], &C[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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