oj.uz

Submission #123029

# Submission time Handle Problem Language Result Execution time Memory
123029 2019-06-30T04:49:14 Z luciocf Valley (BOI19_valley) C++14
100 / 100
 353 ms 46584 KB 
// BOI 2019 - Alpine Valley
// Lúcio Cardoso

#include <bits/stdc++.h>

#define ff first
#define ss second

using namespace std;

const int maxn = 1e5+10;
const int maxl = 20;
const long long inf = 2e18+10;

typedef long long ll;

typedef pair<int, int> pii;

int n, s, q, e;

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

ll dist[maxn], sub[maxn];

pair<int, ll> tab[maxn][maxl];

bool shop[maxn];

pii edge[maxn];

vector<pii> grafo[maxn];

void dfs(int u, int p)
{
	if (shop[u]) sub[u] = 0;

	for (auto pp: grafo[u])
	{
		int v = pp.first, d = w[pp.second];
		if (v == p) continue;

		pai[v] = u, nivel[v] = nivel[u]+1;
		dist[v] = dist[u]+1ll*d;

		dfs(v, u);

		sub[u] = min(sub[u], sub[v]+1ll*d);
	}
}

void build(void)
{
	for (int i = 1; i <= n; i++)
	{
		tab[i][0].ff = pai[i];
		tab[i][0].ss = inf;

		if (sub[i] != inf) tab[i][0].ss = min(tab[i][0].ss, sub[i]-dist[i]);
		if (sub[pai[i]] != inf) tab[i][0].ss = min(tab[i][0].ss, sub[pai[i]]-dist[pai[i]]);
	}

	for (int j = 1; j < maxl; j++)
	{
		for (int i = 1; i <= n; i++)
		{
			tab[i][j].ff = tab[tab[i][j-1].ff][j-1].ff;
			tab[i][j].ss = min(tab[i][j-1].ss, tab[tab[i][j-1].ff][j-1].ss);
		}
	}
}

int lca(int u, int v)
{
	if (nivel[u] < nivel[v]) swap(u, v);

	for (int i = maxl-1; i >= 0; i--)
		if (nivel[u] - (1<<i) >= nivel[v])
			u = tab[u][i].ff;

	if (u == v) return u;

	for (int i = maxl-1; i >= 0; i--)
		if (tab[u][i].ff && tab[v][i].ff && tab[u][i].ff != tab[v][i].ff)
			u = tab[u][i].ff, v = tab[v][i].ff;

	return pai[u];
}

ll get(int u, int v)
{
	ll ans = (sub[u] == inf ? inf : sub[u]-dist[u]);

	for (int i = maxl-1; i >= 0; i--)
		if (nivel[u] - (1<<i) >= nivel[v])
			ans = min(ans, tab[u][i].ss), u = tab[u][i].ff;

	return ans;
}

int main(void)
{
	scanf("%d %d %d %d", &n, &s, &q, &e);

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

		w[i] = c, edge[i] = {u, v};
		grafo[u].push_back({v, i}); grafo[v].push_back({u, i});
	}

	for (int i = 1; i <= s; i++)
	{
		int c;
		scanf("%d", &c);
		shop[c] = 1;
	}

	for (int i = 1; i <= n; i++)
		sub[i] = inf;

	dfs(e, 0); build();

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

		int a = edge[r].first, b = edge[r].second;

		if (nivel[a] > nivel[b]) swap(a, b);

		if (lca(u, b) != b) printf("escaped\n");
		else
		{
			ll ans = get(u, b);

			if (ans == inf) printf("oo\n");
			else printf("%lld\n", ans+dist[u]);
		}
	}
}

Compilation message

valley.cpp: In function 'int main()':
valley.cpp:104:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d %d", &n, &s, &q, &e);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:109:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &u, &v, &c);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:118:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &c);
   ~~~~~^~~~~~~~~~
valley.cpp:130:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &r, &u);
   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 2808 KB Output is correct
2 Correct 8 ms 2808 KB Output is correct
3 Correct 8 ms 2808 KB Output is correct
4 Correct 8 ms 2936 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 2808 KB Output is correct
2 Correct 8 ms 2808 KB Output is correct
3 Correct 8 ms 2808 KB Output is correct
4 Correct 8 ms 2936 KB Output is correct
5 Correct 5 ms 3064 KB Output is correct
6 Correct 5 ms 3064 KB Output is correct
7 Correct 5 ms 3064 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 5 ms 3064 KB Output is correct
10 Correct 5 ms 3064 KB Output is correct
11 Correct 5 ms 3064 KB Output is correct
12 Correct 5 ms 3064 KB Output is correct
13 Correct 5 ms 3192 KB Output is correct
14 Correct 5 ms 3192 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 208 ms 42248 KB Output is correct
2 Correct 236 ms 41820 KB Output is correct
3 Correct 277 ms 41848 KB Output is correct
4 Correct 280 ms 43640 KB Output is correct
5 Correct 328 ms 43704 KB Output is correct
6 Correct 353 ms 45524 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 2808 KB Output is correct
2 Correct 8 ms 2808 KB Output is correct
3 Correct 8 ms 2808 KB Output is correct
4 Correct 8 ms 2936 KB Output is correct
5 Correct 5 ms 3064 KB Output is correct
6 Correct 5 ms 3064 KB Output is correct
7 Correct 5 ms 3064 KB Output is correct
8 Correct 5 ms 3064 KB Output is correct
9 Correct 5 ms 3064 KB Output is correct
10 Correct 5 ms 3064 KB Output is correct
11 Correct 5 ms 3064 KB Output is correct
12 Correct 5 ms 3064 KB Output is correct
13 Correct 5 ms 3192 KB Output is correct
14 Correct 5 ms 3192 KB Output is correct
15 Correct 208 ms 42248 KB Output is correct
16 Correct 236 ms 41820 KB Output is correct
17 Correct 277 ms 41848 KB Output is correct
18 Correct 280 ms 43640 KB Output is correct
19 Correct 328 ms 43704 KB Output is correct
20 Correct 353 ms 45524 KB Output is correct
21 Correct 183 ms 42204 KB Output is correct
22 Correct 206 ms 41880 KB Output is correct
23 Correct 221 ms 41692 KB Output is correct
24 Correct 249 ms 43952 KB Output is correct
25 Correct 266 ms 46584 KB Output is correct
26 Correct 193 ms 42232 KB Output is correct
27 Correct 216 ms 42104 KB Output is correct
28 Correct 223 ms 41876 KB Output is correct
29 Correct 266 ms 43256 KB Output is correct
30 Correct 296 ms 44772 KB Output is correct
31 Correct 209 ms 42424 KB Output is correct
32 Correct 214 ms 41976 KB Output is correct
33 Correct 240 ms 42060 KB Output is correct
34 Correct 262 ms 43776 KB Output is correct
35 Correct 264 ms 46456 KB Output is correct
36 Correct 233 ms 44408 KB Output is correct