Submission #114791

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
114791	2019-06-02T17:41:26 Z	luciocf	Pipes (BOI13_pipes)	C++14	100 / 100	285 ms	17008 KB

pipes

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5+10;

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

int n, m;

int c[maxn];

int ans[maxn];

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

int firstCycle=-1, lastCycle=-1, lastEdge=-1;

bool mark[maxn], inCycle[maxn], ok=1;

vector<pii> grafo[maxn];

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

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

		if (mark[v])
		{
			if (v == p) continue;

			firstCycle = u, lastCycle = v, lastEdge = e;

			if (abs(nivel[u]-nivel[v])%2 == 1)
				ok = 0;

			continue;
		}

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

		dfs(v, u);
	}
}

void markCycle(void)
{
	if (firstCycle == -1) return;

	int v = lastCycle;

	while (true)
	{
		inCycle[v] = true;

		if (v == firstCycle) break;

		v = pai[v];
	}
}

void solve(int u)
{
	mark[u] = true;

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

		if (mark[v]) continue;

		solve(v);

		if (!inCycle[v])
		{
			ans[e] = 2*c[v];
			c[u] -= ans[e]/2, c[v] = 0;
		}
	}
}

void solveCycle(void)
{
	if (firstCycle == -1) return;

	int v = lastCycle, sign = 1;
	ll sum = 0ll;

	while (true)
	{
		sum += 1ll*sign*c[v];

		if (v == firstCycle) break;

		sign *= -1, v = pai[v];
	}

	ans[lastEdge] = sum;

	int prev = ans[lastEdge];
	v = lastCycle;

	while (v != firstCycle)
	{
		int e = edgePai[v];

		ans[e] = 2*c[v] - prev;

		v = pai[v], prev = ans[e];
	}
}

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

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

	if (m > n)
	{
		printf("0\n");
		return 0;
	}

	dfs(1, 0);

	if (!ok)
	{
		printf("0\n");
		return 0;
	}

	markCycle();

	memset(mark, 0, sizeof mark);

	if (firstCycle == -1)
		solve(1);
	else
		solve(firstCycle);

	solveCycle();

	for (int i = 1; i <= m; i++)
		printf("%d\n", ans[i]);
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:119:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:122:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &c[i]);
   ~~~~~^~~~~~~~~~~~~
pipes.cpp:127:8: 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	7 ms	2816 KB	Output is correct
2	Correct	6 ms	2816 KB	Output is correct
3	Correct	5 ms	2944 KB	Output is correct
4	Correct	96 ms	8952 KB	Output is correct
5	Correct	2 ms	2816 KB	Output is correct
6	Correct	4 ms	2816 KB	Output is correct
7	Correct	4 ms	2816 KB	Output is correct
8	Correct	4 ms	2816 KB	Output is correct
9	Correct	5 ms	2860 KB	Output is correct
10	Correct	4 ms	2816 KB	Output is correct
11	Correct	5 ms	2816 KB	Output is correct
12	Correct	5 ms	2816 KB	Output is correct
13	Correct	65 ms	7672 KB	Output is correct
14	Correct	85 ms	8568 KB	Output is correct
15	Correct	87 ms	8924 KB	Output is correct
16	Correct	71 ms	8040 KB	Output is correct
17	Correct	77 ms	8824 KB	Output is correct
18	Correct	94 ms	8852 KB	Output is correct
19	Correct	95 ms	10740 KB	Output is correct
20	Correct	3 ms	2816 KB	Output is correct
21	Correct	4 ms	2816 KB	Output is correct
22	Correct	100 ms	9052 KB	Output is correct
23	Correct	78 ms	7696 KB	Output is correct
24	Correct	104 ms	8924 KB	Output is correct
25	Correct	79 ms	7932 KB	Output is correct

Subtask #2

70.0 / 70.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	4 ms	2816 KB	Output is correct
2	Correct	5 ms	2816 KB	Output is correct
3	Correct	68 ms	9692 KB	Output is correct
4	Correct	70 ms	6392 KB	Output is correct
5	Correct	62 ms	6520 KB	Output is correct
6	Correct	277 ms	17008 KB	Output is correct
7	Correct	4 ms	2816 KB	Output is correct
8	Correct	4 ms	2816 KB	Output is correct
9	Correct	4 ms	2688 KB	Output is correct
10	Correct	4 ms	2688 KB	Output is correct
11	Correct	4 ms	2688 KB	Output is correct
12	Correct	4 ms	2688 KB	Output is correct
13	Correct	3 ms	2688 KB	Output is correct
14	Correct	4 ms	2816 KB	Output is correct
15	Correct	4 ms	2944 KB	Output is correct
16	Correct	4 ms	2816 KB	Output is correct
17	Correct	4 ms	2816 KB	Output is correct
18	Correct	4 ms	2688 KB	Output is correct
19	Correct	4 ms	2688 KB	Output is correct
20	Correct	4 ms	2688 KB	Output is correct
21	Correct	4 ms	2816 KB	Output is correct
22	Correct	4 ms	2944 KB	Output is correct
23	Correct	81 ms	9976 KB	Output is correct
24	Correct	103 ms	11128 KB	Output is correct
25	Correct	69 ms	9744 KB	Output is correct
26	Correct	60 ms	6420 KB	Output is correct
27	Correct	60 ms	6264 KB	Output is correct
28	Correct	60 ms	6776 KB	Output is correct
29	Correct	206 ms	14348 KB	Output is correct
30	Correct	116 ms	12408 KB	Output is correct
31	Correct	109 ms	12632 KB	Output is correct
32	Correct	94 ms	9720 KB	Output is correct
33	Correct	73 ms	10364 KB	Output is correct
34	Correct	56 ms	6352 KB	Output is correct
35	Correct	57 ms	6392 KB	Output is correct
36	Correct	67 ms	6752 KB	Output is correct
37	Correct	285 ms	16988 KB	Output is correct
38	Correct	139 ms	12024 KB	Output is correct
39	Correct	112 ms	9464 KB	Output is correct
40	Correct	118 ms	11076 KB	Output is correct
41	Correct	82 ms	11576 KB	Output is correct
42	Correct	63 ms	6264 KB	Output is correct
43	Correct	69 ms	6268 KB	Output is correct
44	Correct	61 ms	6612 KB	Output is correct
45	Correct	189 ms	15176 KB	Output is correct
46	Correct	119 ms	12840 KB	Output is correct
47	Correct	113 ms	11000 KB	Output is correct
48	Correct	124 ms	12408 KB	Output is correct
49	Correct	71 ms	8440 KB	Output is correct
50	Correct	64 ms	6484 KB	Output is correct
51	Correct	56 ms	6520 KB	Output is correct
52	Correct	58 ms	6264 KB	Output is correct
53	Correct	203 ms	14968 KB	Output is correct
54	Correct	113 ms	11660 KB	Output is correct