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답안 #91189

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
91189 2018-12-26T13:37:38 Z daniel_02 관광지 (IZhO14_shymbulak) C++11
100 / 100
 1057 ms 39472 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 6 ms 5400 KB Output is correct
3 Correct 6 ms 5400 KB Output is correct
4 Correct 6 ms 5400 KB Output is correct
5 Correct 6 ms 5400 KB Output is correct
6 Correct 5 ms 5452 KB Output is correct
7 Correct 6 ms 5452 KB Output is correct
8 Correct 5 ms 5452 KB Output is correct
9 Correct 6 ms 5452 KB Output is correct
10 Correct 6 ms 5452 KB Output is correct
11 Correct 5 ms 5452 KB Output is correct
12 Correct 5 ms 5452 KB Output is correct
13 Correct 6 ms 5452 KB Output is correct
14 Correct 7 ms 5496 KB Output is correct
15 Correct 6 ms 5496 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5764 KB Output is correct
2 Correct 6 ms 5764 KB Output is correct
3 Correct 7 ms 5764 KB Output is correct
4 Correct 7 ms 5764 KB Output is correct
5 Correct 10 ms 6180 KB Output is correct
6 Correct 12 ms 6304 KB Output is correct
7 Correct 11 ms 6304 KB Output is correct
8 Correct 11 ms 6304 KB Output is correct
9 Correct 10 ms 6304 KB Output is correct
10 Correct 10 ms 6304 KB Output is correct

Subtask #3
50.0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Correct 255 ms 21024 KB Output is correct
2 Correct 258 ms 22380 KB Output is correct
3 Correct 140 ms 29924 KB Output is correct
4 Correct 115 ms 29924 KB Output is correct
5 Correct 122 ms 29924 KB Output is correct
6 Correct 547 ms 34996 KB Output is correct
7 Correct 389 ms 34996 KB Output is correct
8 Correct 223 ms 38228 KB Output is correct
9 Correct 268 ms 38600 KB Output is correct
10 Correct 212 ms 39472 KB Output is correct
11 Correct 937 ms 39472 KB Output is correct
12 Correct 1057 ms 39472 KB Output is correct