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Submission #197044

# Submission time Handle Problem Language Result Execution time Memory
197044 2020-01-18T09:52:24 Z arnold518 Valley (BOI19_valley) C++14
100 / 100
 338 ms 60280 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e5;
const ll INF = 1e15;

struct Edge { int u, v, w; };

int N, S, Q, E;
vector<pii> adj[MAXN+10];
Edge edge[MAXN+10];
int C[MAXN+10];

int L[MAXN+10], R[MAXN+10], cnt, par[MAXN+10][35], dep[MAXN+10];
ll D[MAXN+10], EE[MAXN+10][35], F[MAXN+10];

bool reach(int I, int u, int v)
{
	bool a=(L[edge[I].v]<=L[u] && L[u]<=R[edge[I].v]);
	bool b=(L[edge[I].v]<=L[v] && L[v]<=R[edge[I].v]);
	return a==b;
}

void dfs(int now, int bef, ll dist, int depp)
{
	par[now][0]=bef;
	L[now]=R[now]=++cnt;

	D[now]=10*INF;
	if(C[now]) D[now]=dist;

	dep[now]=depp;

	for(auto nxt : adj[now])
	{
		if(nxt.first==bef) continue;
		dfs(nxt.first, now, dist+nxt.second, depp+1);
		R[now]=max(R[now], R[nxt.first]);
		D[now]=min(D[now], D[nxt.first]);
	}

	F[now]=dist;
	EE[now][0]=D[now]-2*dist;

	//printf("%d : %lld\n", now, EE[now][0]);
}

int main()
{
	int i, j;

	scanf("%d%d%d%d", &N, &S, &Q, &E);
	for(i=1; i<N; i++)
	{
		int u, v, w;
		scanf("%d%d%d", &u, &v, &w);
		adj[u].push_back({v, w});
		adj[v].push_back({u, w});
		edge[i]={u, v, w};
	}

	for(i=1; i<=S; i++)
	{
		int t;
		scanf("%d", &t);
		C[t]=1;
	}

	dfs(E, E, 0, 1);
	for(i=1; i<N; i++) if(L[edge[i].u]>L[edge[i].v]) swap(edge[i].u, edge[i].v);

	for(i=1; i<=20; i++) for(j=1; j<=N; j++) par[j][i]=par[par[j][i-1]][i-1], EE[j][i]=min(EE[j][i-1], EE[par[j][i-1]][i-1]);

	while(Q--)
	{
		int A, B;
		scanf("%d%d", &A, &B);

		if(reach(A, E, B)) { printf("escaped\n"); continue; }
		
		int now=B, to=edge[A].v;
		//printf("%d %d\n", now, to);
		ll ans=INF;
		if(C[now]) ans=0;
		for(i=20; i>=0; i--)
		{
			//printf("%d %d\n", par[now][i], i);
			if(dep[par[now][i]]>=dep[to])
			{
				ans=min(ans, EE[now][i]+F[B]);
				now=par[now][i];
			}
		}
		ans=min(ans, EE[to][0]+F[B]);

		if(ans==INF) printf("oo\n");
		else printf("%lld\n", ans);
	}
}

Compilation message

valley.cpp: In function 'int main()':
valley.cpp:56:7: 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:60:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d", &u, &v, &w);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~
valley.cpp:69:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &t);
   ~~~~~^~~~~~~~~~
valley.cpp:81:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &A, &B);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2808 KB Output is correct
2 Correct 7 ms 2808 KB Output is correct
3 Correct 7 ms 2936 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 6 ms 2808 KB Output is correct
2 Correct 7 ms 2808 KB Output is correct
3 Correct 7 ms 2936 KB Output is correct
4 Correct 8 ms 2936 KB Output is correct
5 Correct 6 ms 3320 KB Output is correct
6 Correct 9 ms 3320 KB Output is correct
7 Correct 6 ms 3320 KB Output is correct
8 Correct 6 ms 3192 KB Output is correct
9 Correct 3 ms 3320 KB Output is correct
10 Correct 5 ms 3268 KB Output is correct
11 Correct 6 ms 3192 KB Output is correct
12 Correct 5 ms 3320 KB Output is correct
13 Correct 7 ms 3320 KB Output is correct
14 Correct 6 ms 3320 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 280 ms 52732 KB Output is correct
2 Correct 280 ms 52380 KB Output is correct
3 Correct 294 ms 52244 KB Output is correct
4 Correct 306 ms 54188 KB Output is correct
5 Correct 297 ms 54264 KB Output is correct
6 Correct 328 ms 56056 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2808 KB Output is correct
2 Correct 7 ms 2808 KB Output is correct
3 Correct 7 ms 2936 KB Output is correct
4 Correct 8 ms 2936 KB Output is correct
5 Correct 6 ms 3320 KB Output is correct
6 Correct 9 ms 3320 KB Output is correct
7 Correct 6 ms 3320 KB Output is correct
8 Correct 6 ms 3192 KB Output is correct
9 Correct 3 ms 3320 KB Output is correct
10 Correct 5 ms 3268 KB Output is correct
11 Correct 6 ms 3192 KB Output is correct
12 Correct 5 ms 3320 KB Output is correct
13 Correct 7 ms 3320 KB Output is correct
14 Correct 6 ms 3320 KB Output is correct
15 Correct 280 ms 52732 KB Output is correct
16 Correct 280 ms 52380 KB Output is correct
17 Correct 294 ms 52244 KB Output is correct
18 Correct 306 ms 54188 KB Output is correct
19 Correct 297 ms 54264 KB Output is correct
20 Correct 328 ms 56056 KB Output is correct
21 Correct 255 ms 55716 KB Output is correct
22 Correct 290 ms 55288 KB Output is correct
23 Correct 283 ms 55160 KB Output is correct
24 Correct 330 ms 57336 KB Output is correct
25 Correct 299 ms 60092 KB Output is correct
26 Correct 338 ms 56056 KB Output is correct
27 Correct 257 ms 55672 KB Output is correct
28 Correct 268 ms 55492 KB Output is correct
29 Correct 289 ms 57020 KB Output is correct
30 Correct 302 ms 58232 KB Output is correct
31 Correct 253 ms 56208 KB Output is correct
32 Correct 259 ms 55752 KB Output is correct
33 Correct 274 ms 55800 KB Output is correct
34 Correct 299 ms 57592 KB Output is correct
35 Correct 283 ms 60280 KB Output is correct
36 Correct 282 ms 57720 KB Output is correct