oj.uz

Submission #91188

# Submission time Handle Problem Language Result Execution time Memory
91188 2018-12-26T13:34:49 Z daniel_02 Shymbulak (IZhO14_shymbulak) C++17
100 / 100
 1091 ms 39672 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

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5240 KB Output is correct
2 Correct 5 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 5400 KB Output is correct
7 Correct 6 ms 5400 KB Output is correct
8 Correct 5 ms 5528 KB Output is correct
9 Correct 5 ms 5528 KB Output is correct
10 Correct 5 ms 5528 KB Output is correct
11 Correct 5 ms 5528 KB Output is correct
12 Correct 5 ms 5528 KB Output is correct
13 Correct 5 ms 5528 KB Output is correct
14 Correct 6 ms 5528 KB Output is correct
15 Correct 6 ms 5588 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5712 KB Output is correct
2 Correct 7 ms 5712 KB Output is correct
3 Correct 6 ms 5740 KB Output is correct
4 Correct 6 ms 5740 KB Output is correct
5 Correct 10 ms 6252 KB Output is correct
6 Correct 13 ms 6380 KB Output is correct
7 Correct 12 ms 6380 KB Output is correct
8 Correct 11 ms 6380 KB Output is correct
9 Correct 10 ms 6380 KB Output is correct
10 Correct 11 ms 6396 KB Output is correct

Subtask #3
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 258 ms 21056 KB Output is correct
2 Correct 260 ms 22140 KB Output is correct
3 Correct 148 ms 30004 KB Output is correct
4 Correct 116 ms 30004 KB Output is correct
5 Correct 120 ms 30004 KB Output is correct
6 Correct 569 ms 35132 KB Output is correct
7 Correct 398 ms 35132 KB Output is correct
8 Correct 249 ms 38268 KB Output is correct
9 Correct 254 ms 38628 KB Output is correct
10 Correct 222 ms 39672 KB Output is correct
11 Correct 823 ms 39672 KB Output is correct
12 Correct 1091 ms 39672 KB Output is correct