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Submission #117143

# Submission time Handle Problem Language Result Execution time Memory
117143 2019-06-15T01:12:01 Z luciocf Tug of War (BOI15_tug) C++14
23 / 100
 1854 ms 5496 KB 
#include <bits/stdc++.h>
 
#define ff first
#define ss second
 
using namespace std;
 
const int maxn = 6e4+10;
 
typedef pair<int, int> pii;
 
int n, k;
 
int sa, sb;
 
int pai[maxn], edge[maxn];
 
int firstCycle[maxn], lastCycle[maxn], pesoCycle[2][maxn], inCycle[maxn];
int comp[maxn], back[maxn];
 
int freq[20*maxn];
bool dp[20*maxn];
 
bool mark[maxn];
 
vector<int> V;
 
vector<pii> grafo[maxn];
 
int msb(int x)
{
	return 31-__builtin_clz(x);
}
 
void dfs(int u, int p, int cc)
{
	comp[u] = cc;
 
	for (auto pp: grafo[u])
	{
		int v = pp.ff, w = pp.ss;
 
		if (comp[v])
		{
			if (v != p)
			{
				firstCycle[cc] = u, lastCycle[cc] = v;
				back[cc] = w;
			}
			continue;
		}
 
		pai[v] = u, edge[v] = w;
 
		dfs(v, u, cc);
	}
}
 
void markCycle(int cc)
{
	int u = firstCycle[cc], v = lastCycle[cc];
 
	int s0 = 0, s1 = back[cc];
	bool turn = 0;
 
	while (true)
	{
		inCycle[v] = true;
 
		if (!turn) s0 += edge[v];
		else s1 += edge[v];
 
		if (u == v) break;
 
		v = pai[v];
		turn = !turn;
	}
 
	if (s0 > s1)
	{
		++freq[s1], ++freq[s0-s1];
		pesoCycle[0][cc] = s1, pesoCycle[1][cc] = s0-s1;
	}
	else
	{
		++freq[s0], ++freq[s1-s0];
		pesoCycle[0][cc] = s0, pesoCycle[1][cc] = s1-s0;
	}
}
 
void dfs2(int u)
{
	mark[u] = true;
 
	for (auto pp: grafo[u])
	{
		int v = pp.ff;
		if (!mark[v])
			dfs2(v);
	}
 
	if (!inCycle[u])
	{
		if (u <= n) sa += edge[u];
		else sb += edge[u];
	}
}
 
int main(void)
{
	memset(firstCycle, -1, sizeof firstCycle);
 
	scanf("%d %d", &n, &k);
 
	int S = 0;
 
	for (int i = 1; i <= 2*n; i++)
	{
		int a, b, w;
		scanf("%d %d %d", &a, &b, &w);
 
		b += n;
		S += w;
 
		grafo[a].push_back({b, w});
		grafo[b].push_back({a, w});
	}
 
	int cc = 0;
	for (int i = 1; i <= 2*n; i++)
	{
		if (comp[i]) continue;
 
		dfs(i, 0, ++cc);
 
		if (firstCycle[cc] == -1)
		{
			printf("NO\n");
			return 0;
		}
	}
 
	for (int i = 1; i <= cc; i++)
	{
		markCycle(i);
		dfs2(firstCycle[i]);
	}
 
	for (int i = 0; i <= cc; i++)
	{
		int a = pesoCycle[0][i];
 
		int x = msb(freq[a]);
 
		for (int j = 0; j < x; j++)
			V.push_back((1<<j)*a);
 
		V.push_back(a*(freq[a]-(1<<x)+1));
 
 
		a = pesoCycle[1][i];
 
		x = msb(freq[a]);
 
		for (int j = 0; j < x; j++)
			V.push_back((1<<j)*a);
 
		V.push_back(a*(freq[a]-(1<<x)+1));
	}
 
	// solve a
	dp[0] = 1;
	for (auto w: V)
		for (int i = (S-2*sa)/2; i >= w; i--)
			dp[i] |= dp[i-w];
 
	int mx = 0;
	for (int i = 0; i <= (S-2*sa)/2; i++)
		if (dp[i])
			mx = max(mx, i);
 
	if (S-sb-2*sa-2*mx <= k)
	{
		printf("YES\n");
		return 0;
	}
 
	memset(dp, 0, sizeof dp);
 
	// solve b
	dp[0] = 1;
	for (auto w: V)
		for (int i = (S-2*sb)/2; i >= w; i--)
			dp[i] |= dp[i-w];
 
	mx = 0;
	for (int i = 0; i <= (S-2*sb)/2; i++)
		if (dp[i])
			mx = max(mx, i);
 
	if (S-sa-2*sb-2*mx <= k)
	{
		printf("YES\n");
		return 0;
	}
 
	printf("NO\n");
}

Compilation message

tug.cpp: In function 'int main()':
tug.cpp:113:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &k);
  ~~~~~^~~~~~~~~~~~~~~~~
tug.cpp:120:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &a, &b, &w);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3200 KB Output is correct
2 Correct 3 ms 2048 KB Output is correct
3 Correct 4 ms 3200 KB Output is correct
4 Correct 3 ms 2048 KB Output is correct
5 Correct 4 ms 3200 KB Output is correct
6 Correct 4 ms 3132 KB Output is correct
7 Correct 4 ms 2048 KB Output is correct
8 Correct 3 ms 2048 KB Output is correct
9 Correct 3 ms 2048 KB Output is correct
10 Correct 4 ms 3200 KB Output is correct
11 Correct 3 ms 2048 KB Output is correct
12 Correct 3 ms 2048 KB Output is correct
13 Correct 3 ms 2048 KB Output is correct
14 Correct 3 ms 2048 KB Output is correct
15 Correct 3 ms 2048 KB Output is correct
16 Correct 4 ms 3200 KB Output is correct
17 Correct 3 ms 2048 KB Output is correct
18 Correct 4 ms 2048 KB Output is correct
19 Correct 3 ms 2048 KB Output is correct
20 Correct 3 ms 2048 KB Output is correct
21 Correct 4 ms 1920 KB Output is correct
22 Correct 3 ms 2048 KB Output is correct
23 Incorrect 3 ms 2048 KB Output isn't correct
24 Halted 0 ms 0 KB -

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3200 KB Output is correct
2 Correct 3 ms 2048 KB Output is correct
3 Correct 4 ms 3200 KB Output is correct
4 Correct 3 ms 2048 KB Output is correct
5 Correct 4 ms 3200 KB Output is correct
6 Correct 4 ms 3132 KB Output is correct
7 Correct 4 ms 2048 KB Output is correct
8 Correct 3 ms 2048 KB Output is correct
9 Correct 3 ms 2048 KB Output is correct
10 Correct 4 ms 3200 KB Output is correct
11 Correct 3 ms 2048 KB Output is correct
12 Correct 3 ms 2048 KB Output is correct
13 Correct 3 ms 2048 KB Output is correct
14 Correct 3 ms 2048 KB Output is correct
15 Correct 3 ms 2048 KB Output is correct
16 Correct 4 ms 3200 KB Output is correct
17 Correct 3 ms 2048 KB Output is correct
18 Correct 4 ms 2048 KB Output is correct
19 Correct 3 ms 2048 KB Output is correct
20 Correct 3 ms 2048 KB Output is correct
21 Correct 4 ms 1920 KB Output is correct
22 Correct 3 ms 2048 KB Output is correct
23 Incorrect 3 ms 2048 KB Output isn't correct
24 Halted 0 ms 0 KB -

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 1781 ms 5240 KB Output is correct
2 Correct 14 ms 3200 KB Output is correct
3 Correct 1791 ms 5496 KB Output is correct
4 Correct 14 ms 2944 KB Output is correct
5 Correct 1796 ms 5496 KB Output is correct
6 Correct 14 ms 3072 KB Output is correct
7 Correct 1804 ms 5496 KB Output is correct
8 Correct 15 ms 3200 KB Output is correct
9 Correct 1811 ms 5496 KB Output is correct
10 Correct 14 ms 3072 KB Output is correct
11 Correct 1801 ms 5496 KB Output is correct
12 Correct 13 ms 3200 KB Output is correct
13 Correct 1768 ms 5496 KB Output is correct
14 Correct 1758 ms 5496 KB Output is correct
15 Correct 13 ms 3072 KB Output is correct
16 Correct 1854 ms 5496 KB Output is correct
17 Correct 13 ms 3200 KB Output is correct
18 Correct 1837 ms 5488 KB Output is correct
19 Correct 14 ms 3200 KB Output is correct
20 Correct 1817 ms 5496 KB Output is correct
21 Correct 15 ms 3328 KB Output is correct
22 Correct 557 ms 4048 KB Output is correct

Subtask #4
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 3200 KB Output is correct
2 Correct 3 ms 2048 KB Output is correct
3 Correct 4 ms 3200 KB Output is correct
4 Correct 3 ms 2048 KB Output is correct
5 Correct 4 ms 3200 KB Output is correct
6 Correct 4 ms 3132 KB Output is correct
7 Correct 4 ms 2048 KB Output is correct
8 Correct 3 ms 2048 KB Output is correct
9 Correct 3 ms 2048 KB Output is correct
10 Correct 4 ms 3200 KB Output is correct
11 Correct 3 ms 2048 KB Output is correct
12 Correct 3 ms 2048 KB Output is correct
13 Correct 3 ms 2048 KB Output is correct
14 Correct 3 ms 2048 KB Output is correct
15 Correct 3 ms 2048 KB Output is correct
16 Correct 4 ms 3200 KB Output is correct
17 Correct 3 ms 2048 KB Output is correct
18 Correct 4 ms 2048 KB Output is correct
19 Correct 3 ms 2048 KB Output is correct
20 Correct 3 ms 2048 KB Output is correct
21 Correct 4 ms 1920 KB Output is correct
22 Correct 3 ms 2048 KB Output is correct
23 Incorrect 3 ms 2048 KB Output isn't correct
24 Halted 0 ms 0 KB -