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Submission #91187

# Submission time Handle Problem Language Result Execution time Memory
91187 2018-12-26T13:31:29 Z daniel_02 Shymbulak (IZhO14_shymbulak) C++17
100 / 100
 884 ms 44552 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 = 3e5 + 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

# Verdict Execution time Memory Grader output
1 Correct 8 ms 7672 KB Output is correct
2 Correct 8 ms 7808 KB Output is correct
3 Correct 8 ms 7808 KB Output is correct
4 Correct 9 ms 7904 KB Output is correct
5 Correct 8 ms 7904 KB Output is correct
6 Correct 8 ms 7952 KB Output is correct
7 Correct 8 ms 7952 KB Output is correct
8 Correct 8 ms 7952 KB Output is correct
9 Correct 7 ms 7960 KB Output is correct
10 Correct 8 ms 7960 KB Output is correct
11 Correct 8 ms 7960 KB Output is correct
12 Correct 7 ms 7996 KB Output is correct
13 Correct 7 ms 7996 KB Output is correct
14 Correct 7 ms 8064 KB Output is correct
15 Correct 8 ms 8064 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8192 KB Output is correct
2 Correct 9 ms 8192 KB Output is correct
3 Correct 9 ms 8388 KB Output is correct
4 Correct 9 ms 8388 KB Output is correct
5 Correct 13 ms 8904 KB Output is correct
6 Correct 15 ms 8932 KB Output is correct
7 Correct 14 ms 8980 KB Output is correct
8 Correct 14 ms 9104 KB Output is correct
9 Correct 13 ms 9104 KB Output is correct
10 Correct 13 ms 9116 KB Output is correct

Subtask #3
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 293 ms 25032 KB Output is correct
2 Correct 255 ms 26708 KB Output is correct
3 Correct 137 ms 34292 KB Output is correct
4 Correct 107 ms 34292 KB Output is correct
5 Correct 112 ms 34292 KB Output is correct
6 Correct 647 ms 40200 KB Output is correct
7 Correct 362 ms 40200 KB Output is correct
8 Correct 256 ms 43144 KB Output is correct
9 Correct 244 ms 43480 KB Output is correct
10 Correct 209 ms 44552 KB Output is correct
11 Correct 835 ms 44552 KB Output is correct
12 Correct 884 ms 44552 KB Output is correct