oj.uz

답안 #91190

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
91190 2018-12-26T13:38:22 Z daniel_02 관광지 (IZhO14_shymbulak) C++14
100 / 100
 1035 ms 39568 KB 
#include <bits/stdc++.h>

#define fr first
#define pb push_back
#define sc second
#define ll long long

using namespace std;

const int N = 2e5 + 7;
const int inf = 1e9 + 7;

vector<int>g[N];
int c[N];
set<int, greater<int>>st1;
set<int, greater<int>>st2;
int mp1[N];
int mp2[N];
ll cnt[N];
int qt[N], tin[N], cn, fup[N];
ll mx = -1;
map<pair<int, int>, bool>is_b;
bool us[N];
int ver;
int cycn;

void dfs(int v, int p)
{	
	tin[v] = fup[v] = ++cn;
	us[v] = 1;
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (to == p)continue;
		if (us[to])
		{
			fup[v] = min(fup[v], tin[to]);
		}
		else
		{
			dfs(to, v);
			fup[v] = min(fup[v], fup[to]);
			if (fup[to] > tin[v])
				is_b[{v, to}] = 1, is_b[{to, v}] = 1;
			else
				ver = to;
		}
	}
}
pair<int, int> deep(int v, int p)
{
	ll mxx = -1, mx1 = -1;
	ll eq = 1, eq1 = 1;
	ll col = 0, sm = 0;
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (to == p || !is_b[{v, to}])continue;
		pair<ll, ll> q = deep(to, v);
		if (mxx < q.fr)
		{
			eq1 = eq;
			mx1 = mxx;
			mxx = q.fr;
			eq = q.sc;
			sm = q.sc;
		}
		else
		{
			if (q.fr == mxx){
				eq += q.sc;
				col += (q.sc * sm);
				sm += q.sc;
			}
			if (q.fr == mx1)
				eq1 += q.sc;
			if (q.fr > mx1)
				eq1 = q.sc;
			mx1 = max(mx1, q.fr * 1LL);
		}
	}
	mxx++; mx1++;
	if (mxx != mx1)
	{
		col = eq * eq1;
	}
	mx = max(mxx + mx1, mx);
	cnt[mxx + mx1] += col;
	return {mxx, eq};
}
void dfs1(int v, int p, int id)
{
	us[v] = 1;
	cycn++;
	us[v] = 1;
	int mx = 0;
	int cnt = 0;
	pair<int, int>q = deep(v, p);
	mx = q.fr, cnt = q.sc;
	c[id] = mx;
	qt[id] = cnt;
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (us[to] || is_b[{v, to}])continue;
		dfs1(to, v, id + 1);
	}
}
void dfs2(int v, int p, int id)
{
	us[v] = 1;
	if (id != 0)
	{
		ll len = (*st1.begin()) + id + c[id];
		mx = max(mx, len);
		cnt[len] += (mp1[len - id - c[id]] * 1LL * qt[id]);
		if (st2.size())
		{
			len = (*st2.begin()) - id + c[id];
			mx = max(mx, len);
			cnt[len] += (mp2[len + id - c[id]] * 1LL * qt[id]);
		}
	}
	st1.insert(c[id] - id);
	mp1[c[id] - id] += qt[id];
	int prev = cycn / 2;
	if (id >= prev)
	{
		mp1[c[id - prev] - id + prev] -= qt[id - prev];
		if (mp1[c[id - prev] - id + prev] == 0)
			st1.erase(c[id - prev] - id + prev);
		if (cycn % 2){
			st2.insert(c[id - prev] + cycn + id - prev);
			mp2[c[id - prev] + cycn + id - prev] += qt[id - prev];
		}
	}
	if (cycn % 2 == 0 && id >= prev - 1)
	{
		st2.insert(cycn + (id - prev + 1) + c[id - prev + 1]);
		mp2[cycn + (id - prev + 1) + c[id - prev + 1]] += qt[id - prev + 1];
	}
	for (int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if (is_b[{v, to}] || us[to])continue;
		dfs2(to, v, id + 1);
	}
}
main()
{
	int n;
	
	cin >> n;
	
	for (int i = 1; i <= n; i++)
	{
		int a, b;
		scanf("%d%d", &a, &b);
		g[a].pb(b);
		g[b].pb(a);
	}
	
	dfs(1, 0);
	memset(us, 0, sizeof(us));
	
	dfs1(ver, 0, 0);
	memset(us, 0, sizeof(us));
	dfs2(ver, 0, 0);
	cout << cnt[mx] << endl;
}
/*
 * Find Bridges
 * Assign c[i]s (length of subtree) and q[i] number of them and cyc -> length of cycle 
 * Dance
*/

Compilation message

shymbulak.cpp: In function 'void dfs(int, int)':
shymbulak.cpp:31:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
shymbulak.cpp: In function 'std::pair<int, int> deep(int, int)':
shymbulak.cpp:55:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
shymbulak.cpp: In function 'void dfs1(int, int, int)':
shymbulak.cpp:102:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
shymbulak.cpp: In function 'void dfs2(int, int, int)':
shymbulak.cpp:142:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < g[v].size(); i++)
                  ~~^~~~~~~~~~~~~
shymbulak.cpp: At global scope:
shymbulak.cpp:149:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
shymbulak.cpp: In function 'int main()':
shymbulak.cpp:158:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 5240 KB Output is correct
2 Correct 5 ms 5372 KB Output is correct
3 Correct 5 ms 5476 KB Output is correct
4 Correct 5 ms 5476 KB Output is correct
5 Correct 5 ms 5476 KB Output is correct
6 Correct 5 ms 5476 KB Output is correct
7 Correct 5 ms 5476 KB Output is correct
8 Correct 5 ms 5476 KB Output is correct
9 Correct 5 ms 5476 KB Output is correct
10 Correct 5 ms 5476 KB Output is correct
11 Correct 5 ms 5584 KB Output is correct
12 Correct 5 ms 5584 KB Output is correct
13 Correct 5 ms 5584 KB Output is correct
14 Correct 6 ms 5660 KB Output is correct
15 Correct 7 ms 5660 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 5728 KB Output is correct
2 Correct 6 ms 5728 KB Output is correct
3 Correct 7 ms 5728 KB Output is correct
4 Correct 6 ms 5728 KB Output is correct
5 Correct 10 ms 6244 KB Output is correct
6 Correct 12 ms 6368 KB Output is correct
7 Correct 12 ms 6368 KB Output is correct
8 Correct 11 ms 6368 KB Output is correct
9 Correct 10 ms 6368 KB Output is correct
10 Correct 11 ms 6368 KB Output is correct

Subtask #3
50.0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 242 ms 21128 KB Output is correct
2 Correct 279 ms 22260 KB Output is correct
3 Correct 144 ms 29960 KB Output is correct
4 Correct 115 ms 29960 KB Output is correct
5 Correct 139 ms 29960 KB Output is correct
6 Correct 579 ms 35212 KB Output is correct
7 Correct 379 ms 35212 KB Output is correct
8 Correct 248 ms 38240 KB Output is correct
9 Correct 269 ms 38496 KB Output is correct
10 Correct 240 ms 39568 KB Output is correct
11 Correct 1035 ms 39568 KB Output is correct
12 Correct 1028 ms 39568 KB Output is correct