Submission #106159

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
106159	2019-04-16T22:53:52 Z	luciocf	Pipes (BOI13_pipes)	C++14	74.0741 / 100	356 ms	38392 KB

pipes

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5+10;
const int maxm = 5e5+10;
const int maxl = 20;
const int inf = 2e9+10;

struct T
{
	int x, mx, mi;
} tab[maxn][maxl];

typedef pair<int, int> pii;

int a[maxn], cur[maxn];
pii E[maxm];

int edge[maxn], costEdge[maxm];

int pai[maxn], nivel[maxn];

bool mark[maxn];

vector<pii> grafo[maxn];

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

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

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

		dfs(v, u);

		cur[u] += costEdge[e]/2;
	}

	if (u != 1)
	{
		costEdge[edge[u]] = 2*(a[u]-cur[u]);
		cur[u] = a[u];
	}
}

void init(int n)
{
	for (int i = 1; i <= n; i++)
		for (int j = 0; j < maxl; j++)
			tab[i][j].mx = -inf, tab[i][j].mi = inf;
}

void build(int n)
{
	for (int i = 1; i <= n; i++)
	{
		tab[i][0].x = pai[i];
		tab[i][0].mx = tab[i][0].mi = costEdge[edge[i]];
	}

	for (int j = 1; j < maxl; j++)
	{
		for (int i = 1; i <= n; i++)
		{
			tab[i][j].x = tab[tab[i][j-1].x][j-1].x;
			tab[i][j].mx = max(tab[i][j-1].mx, tab[tab[i][j-1].x][j-1].mx);
			tab[i][j].mi = max(tab[i][j-1].mi, tab[tab[i][j-1].x][j-1].mi);
		}
	}
}

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].x;

	if (u == v) return u;

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

	return pai[u];
}

pii get(int u, int l)
{
	int mx = -inf, mi = inf;

	for (int i = maxl-1; i >= 0; i--)
	{
		if (nivel[u]-(1<<i) >= nivel[l])
		{
			mx = max(mx, tab[u][i].mx);
			mi = min(mi, tab[u][i].mi);
			u = tab[u][i].x;
		}
	}

	return {mx, mi};
}

int main(void)
{
	int n, m;
	scanf("%d %d", &n, &m);

	for (int i = 1; i <= n; i++)
		scanf("%d", &a[i]);

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

		grafo[u].push_back({v, i});
		grafo[v].push_back({u, i});

		E[i] = {u, v};
	}

	memset(costEdge, -1, sizeof costEdge);

	dfs(1, 0);

	if (cur[1] != a[1])
	{
		printf("0\n");
		return 0;
	}

	init(n);
	build(n);

	bool ok = 1;

	for (int i = 1; i <= m; i++)
	{
		if (costEdge[i] == -1)
		{
			int u = E[i].first, v = E[i].second;

			int low = lca(u, v), mx = -inf, mi = inf;

			pii ans = get(u, low);
			mx = max(mx, ans.first); mi = min(mi, ans.second);

			ans = get(v, low);
			mx = max(mx, ans.first); mi = min(mi, ans.second);

			if (mx != 0 || mi != 0)
			{
				ok = 0;
				break;
			}
		}
	}

	if (!ok) printf("0\n");
	else
	{
		for (int i = 1; i <= m; i++)
		{
			if (costEdge[i] == -1) printf("0\n");
			else printf("%d\n", costEdge[i]);
		}
	}
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:115:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:118:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~
pipes.cpp:123:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1

30.0 / 30.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	5 ms	4736 KB	Output is correct
2	Correct	5 ms	4736 KB	Output is correct
3	Correct	7 ms	4992 KB	Output is correct
4	Correct	155 ms	34920 KB	Output is correct
5	Correct	6 ms	4736 KB	Output is correct
6	Correct	5 ms	4736 KB	Output is correct
7	Correct	7 ms	4736 KB	Output is correct
8	Correct	6 ms	4736 KB	Output is correct
9	Correct	8 ms	4992 KB	Output is correct
10	Correct	7 ms	4992 KB	Output is correct
11	Correct	7 ms	4992 KB	Output is correct
12	Correct	7 ms	4992 KB	Output is correct
13	Correct	109 ms	28796 KB	Output is correct
14	Correct	141 ms	33400 KB	Output is correct
15	Correct	189 ms	35192 KB	Output is correct
16	Correct	153 ms	30608 KB	Output is correct
17	Correct	151 ms	35064 KB	Output is correct
18	Correct	183 ms	35140 KB	Output is correct
19	Correct	217 ms	36984 KB	Output is correct
20	Correct	5 ms	4736 KB	Output is correct
21	Correct	6 ms	4992 KB	Output is correct
22	Correct	152 ms	35196 KB	Output is correct
23	Correct	111 ms	28924 KB	Output is correct
24	Correct	145 ms	35192 KB	Output is correct
25	Correct	133 ms	30076 KB	Output is correct

Subtask #2

44.0740740741 / 70.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	6 ms	4608 KB	Output isn't correct
2	Incorrect	8 ms	4736 KB	Output isn't correct
3	Correct	244 ms	34852 KB	Output is correct
4	Correct	101 ms	14328 KB	Output is correct
5	Correct	101 ms	10976 KB	Output is correct
6	Correct	352 ms	28344 KB	Output is correct
7	Incorrect	5 ms	4608 KB	Output isn't correct
8	Incorrect	5 ms	4608 KB	Output isn't correct
9	Correct	5 ms	4736 KB	Output is correct
10	Correct	7 ms	4736 KB	Output is correct
11	Correct	5 ms	4608 KB	Output is correct
12	Correct	6 ms	4608 KB	Output is correct
13	Correct	6 ms	4608 KB	Output is correct
14	Incorrect	6 ms	4736 KB	Output isn't correct
15	Incorrect	6 ms	4736 KB	Output isn't correct
16	Incorrect	6 ms	4736 KB	Output isn't correct
17	Correct	8 ms	4992 KB	Output is correct
18	Correct	6 ms	4736 KB	Output is correct
19	Correct	6 ms	4736 KB	Output is correct
20	Correct	6 ms	4736 KB	Output is correct
21	Correct	7 ms	4864 KB	Output is correct
22	Incorrect	8 ms	4736 KB	Output isn't correct
23	Incorrect	91 ms	12140 KB	Output isn't correct
24	Incorrect	118 ms	13364 KB	Output isn't correct
25	Correct	191 ms	34936 KB	Output is correct
26	Correct	97 ms	13944 KB	Output is correct
27	Correct	104 ms	14072 KB	Output is correct
28	Correct	111 ms	11176 KB	Output is correct
29	Correct	298 ms	25080 KB	Output is correct
30	Incorrect	99 ms	14712 KB	Output isn't correct
31	Incorrect	110 ms	14712 KB	Output isn't correct
32	Incorrect	107 ms	11908 KB	Output isn't correct
33	Correct	183 ms	36968 KB	Output is correct
34	Correct	93 ms	13404 KB	Output is correct
35	Correct	97 ms	14348 KB	Output is correct
36	Correct	84 ms	11000 KB	Output is correct
37	Correct	356 ms	28416 KB	Output is correct
38	Incorrect	93 ms	14200 KB	Output isn't correct
39	Incorrect	98 ms	11644 KB	Output isn't correct
40	Incorrect	95 ms	13276 KB	Output isn't correct
41	Correct	205 ms	38392 KB	Output is correct
42	Correct	99 ms	13560 KB	Output is correct
43	Correct	107 ms	14516 KB	Output is correct
44	Correct	95 ms	11000 KB	Output is correct
45	Correct	262 ms	23756 KB	Output is correct
46	Incorrect	105 ms	15096 KB	Output isn't correct
47	Incorrect	104 ms	13272 KB	Output isn't correct
48	Incorrect	112 ms	14576 KB	Output isn't correct
49	Correct	163 ms	33576 KB	Output is correct
50	Correct	89 ms	13488 KB	Output is correct
51	Correct	98 ms	12548 KB	Output is correct
52	Correct	89 ms	11896 KB	Output is correct
53	Correct	262 ms	24496 KB	Output is correct
54	Incorrect	89 ms	13816 KB	Output isn't correct