Submission #254876

#	Time	Username	Problem	Language	Result	Execution time	Memory
254876		MrRobot_28	Lampice (COCI19_lampice)	C++17	17 / 110	5087 ms	135332 KiB

lampice

#include <bits/stdc++.h>
using namespace std;
#define int long long
int n;
string s;
vector <vector <int> > g;
vector <int> _sz, h;
vector <bool> used;
bool flag;
int len;
vector <int> hash1, hash2;
map <pair <int, int>, int> mp, mp1;
vector <int> power;
const int const1 = 1e9 + 7;
void dfs1(int v, int p = -1)
{
	_sz[v] = 1;
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(to != p && !used[to])
		{
			h[to] = h[v] + 1;
			dfs1(to, v);
			_sz[v] += _sz[to];
		}
	}
}
void build(int v, int p = -1)
{
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(to != p && !used[to])
		{
			h[to] = h[v] + 1;
			build(to, v);
		}
	}
}
int centroid(int v, int szall, int p = -1)
{
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(to == p || used[to])
		{
			continue;
		}
		if(_sz[to] * 2 > szall)
		{
			return centroid(to, szall, v);
		}
	}
	return v;
}
vector <int> vec;
void dfs2(int v, int p)
{
	int ourhash = hash1[v];
	bool fl = false;
	vec.push_back(v);
	if(len >= h[v])
	{
	if(len - h[v] < h[v])
	{
		int len1 = len - h[v];
		ourhash -= hash1[vec[vec.size() - len1 - 1]] * power[len1] % const1;
		if(hash1[vec[vec.size() -  len1 - 1]] == hash2[vec[vec.size() - len1 - 1]])
		{
			fl = true;
		}
		if(ourhash < 0)
		{
			ourhash += const1;
		}
	}
	else
	{
		fl = true;
	}
	if(fl && mp[{ourhash, len - h[v]}] != 0)
	{
		flag = true;
	}
	}
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(!used[to] && to != p)
		{
			hash1[to] = hash1[v] * 27 % const1 + s[to] - 'a' + 1;
			if(hash1[to] >= const1)
			{
				hash1[to] -= const1;
			}
			hash2[to] = hash2[v] + power[h[v]] * (s[to] - 'a' + 1) % const1;
			if(hash2[to] >= const1)
			{
				hash2[to] -= const1;
			}
				dfs2(to, v);
		}
	}
	vec.pop_back();
}
vector <pair <int, int> > mass;
void dfs3(int v, int p)
{
	int ourhash = hash1[v];
	bool fl = false;
	vec.push_back(v);
	if(len >= h[v] + 1)
	{
	if(len - (h[v] + 1) < (h[v] + 1))
	{
		int len1 = len - (h[v] + 1);
		ourhash -= hash1[vec[vec.size() - len1 - 1]] * power[len1] % const1;
		if(ourhash < 0)
		{
			ourhash += const1;
		}
		if(hash1[vec[vec.size() - len1 - 1]] == hash2[vec[vec.size() - len1 - 1]])
		{
			fl = true;
		}
	}
	else
	{
		fl = true;
	}
	if(fl)
	{
		mass.push_back({ourhash, h[v] + 1});
		mp[{ourhash, h[v] + 1}]++;
	}
	}	
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(to != p && !used[to])
		{
			hash1[to] = hash1[v] * 27 % const1 + s[to] - 'a' + 1;
			if(hash1[to] >= const1)
			{
				hash1[to] -= const1;
			}
			hash2[to] = hash2[v] + power[h[to]] * (s[to] - 'a' + 1) % const1;
			if(hash2[to] >= const1)
			{
				hash2[to] -= const1;
			}
			dfs3(to, v);
		}
	}
	vec.pop_back();
}
void go_to(int v)
{
	dfs1(v);
	v = centroid(v, _sz[v]);
	h[v] = 0;
	build(v);
	used[v] = 1;
	hash1[v] = hash2[v] = s[v] - 'a' + 1;
	mp[{s[v] - 'a' + 1, 1}] = 1;
	mass.push_back({s[v] -'a' + 1, 1});
	for(int i = 0; i  <g[v].size(); i++)
	{
		int to = g[v][i];
		if(!used[to])
		{
			hash1[to] = hash2[to] = s[to] - 'a' + 1;
			dfs2(to, v);
			vec.clear();
			vec.push_back(v);
			hash1[to] = (s[v] - 'a' + 1) * 27 + (s[to] - 'a' + 1);
			hash2[to] = (s[v] - 'a' + 1) + 27 * (s[to] - 'a' + 1);
			dfs3(to, v);
			vec.clear();
		}
	}
	while(mass.size() > 0)
	{
		pair <int, int> v = mass.back();
		mp[v]--;
		mass.pop_back();
	}
	for(int i = 0; i < g[v].size(); i++)
	{
		int to = g[v][i];
		if(!used[to])
		{
			go_to(to);
		}
	}
}
signed main(){
//	ios_base::sync_with_stdio(false);
//	cin.tie(NULL);
//	cout.tie(NULL);
	cin >> n;
	used.resize(n);
	_sz.resize(n);
	cin >> s;
	power.resize(n + 1);
	power[0] = 1;
	for(int i = 1; i <= n; i++)
	{
		power[i] = power[i - 1] * 27 % const1;
	}
	h.resize(n);
	hash1.resize(n);
	hash2.resize(n);
	g.resize(n);
	for(int i = 0; i < n - 1; i++)
	{
		int a, b;
		cin >> a >> b;
		a--;
		b--;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	int l = 0, r = n / 2 + 1;
	while(r - l > 1)
	{
		int midd = (r + l) / 2;
		len = midd * 2;
		for(int i = 0; i < n; i++)
		{
			used[i] = 0;
		}
		flag = false;
		go_to(0);
		if(flag)
		{
			l = midd;
		}
		else
		{
			r = midd;
		}
	}
	int l1 = 0, r1 = n / 2 + 1;
	while(r1 - l1 > 1)
	{
		int midd = (r1 + l1) / 2;
		len = midd * 2 + 1;
		for(int i = 0; i < n; i++)
		{
			used[i] = 0;
		}
		flag = false;
		go_to(0);
		if(flag)
		{
			l1 = midd;
		}
		else
		{
			r1 = midd;
		}
	}
	cout << max(l * 2, l1 * 2 + 1);
	return 0;
}

Compilation message (stderr)

lampice.cpp: In function 'void dfs1(long long int, long long int)':
lampice.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~
lampice.cpp: In function 'void build(long long int, long long int)':
lampice.cpp:31:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~
lampice.cpp: In function 'long long int centroid(long long int, long long int, long long int)':
lampice.cpp:43:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~
lampice.cpp: In function 'void dfs2(long long int, long long int)':
lampice.cpp:87:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~
lampice.cpp: In function 'void dfs3(long long int, long long int)':
lampice.cpp:138:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~
lampice.cpp: In function 'void go_to(long long int)':
lampice.cpp:168:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i  <g[v].size(); i++)
                 ~~~^~~~~~~~~~~~
lampice.cpp:189:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < g[v].size(); i++)
                 ~~^~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 0 / 25
• Subtask 3: 0 / 31
• Subtask 4: 0 / 37