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답안 #115941

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
115941 2019-06-10T02:32:45 Z luciocf Tug of War (BOI15_tug) C++14
23 / 100
 1950 ms 6272 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];
 
map<int, int> freq;
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[s0], ++freq[s1-s0];
		pesoCycle[0][cc] = s1, pesoCycle[1][cc] = s0-s1;
	}
	else
	{
		++freq[s1], ++freq[s0-s1];
		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[i]-(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[i]-(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

# 결과 실행 시간 메모리 Grader output
1 Runtime error 10 ms 6272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -

Subtask #2
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 10 ms 6272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -

Subtask #3
23.0 / 23.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1874 ms 5552 KB Output is correct
2 Correct 14 ms 2944 KB Output is correct
3 Correct 1908 ms 5552 KB Output is correct
4 Correct 12 ms 2688 KB Output is correct
5 Correct 1863 ms 5552 KB Output is correct
6 Correct 13 ms 2816 KB Output is correct
7 Correct 1855 ms 5552 KB Output is correct
8 Correct 15 ms 2944 KB Output is correct
9 Correct 1871 ms 5524 KB Output is correct
10 Correct 13 ms 2944 KB Output is correct
11 Correct 1916 ms 5552 KB Output is correct
12 Correct 14 ms 2944 KB Output is correct
13 Correct 1891 ms 5552 KB Output is correct
14 Correct 1950 ms 5552 KB Output is correct
15 Correct 13 ms 2816 KB Output is correct
16 Correct 1900 ms 5552 KB Output is correct
17 Correct 13 ms 2944 KB Output is correct
18 Correct 1850 ms 5552 KB Output is correct
19 Correct 13 ms 2944 KB Output is correct
20 Correct 1877 ms 5552 KB Output is correct
21 Correct 13 ms 3072 KB Output is correct
22 Correct 537 ms 3992 KB Output is correct

Subtask #4
0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 10 ms 6272 KB Execution killed with signal 11 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -