oj.uz

Submission #703248

# Submission time Handle Problem Language Result Execution time Memory
703248 2023-02-26T17:28:17 Z 600Mihnea Palindromes (APIO14_palindrome) C++17
100 / 100
 89 ms 87552 KB 
#include <cmath>
#include <functional>
#include <fstream>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <list>
#include <time.h>
#include <math.h>
#include <random>
#include <deque>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <cassert>
#include <bitset>
#include <sstream>
#include <chrono>
#include <cstring>
#include <numeric>

using namespace std;

#define int long long

int dumb(string s)
{
	int n = (int)s.size();
	vector<vector<int>> lcp(n, vector<int>(n, 0));
	vector<vector<bool>> ispal(n, vector<bool>(n, 0));

	for (int i = 0; i < n; i++)
	{
		lcp[i][i] = n - i;
	}
	for (int i = n - 1; i >= 0; i--)
	{
		for (int j = i + 1; j < n; j++)
		{
			if (s[i] == s[j])
			{
				int c = 0;
				if (i + 1 < n && j + 1 < n)
				{
					c += lcp[i + 1][j + 1];
				}
				lcp[i][j] = lcp[j][i] = 1 + c;
			}
		}
	}
	for (int i = 0; i < n; i++)
	{
		ispal[i][i] = 1;
	}
	for (int i = 0; i + 1 < n; i++)
	{
		ispal[i][i + 1] = (s[i] == s[i + 1]);
	}
	for (int len = 3; len <= n; len++)
	{
		for (int i = 0; i + len - 1 < n; i++)
		{
			int j = i + len - 1;
			ispal[i][j] = ispal[i + 1][j - 1] & (s[i] == s[j]);
		}
	}
	int sol = 0;
	for (int len = 1; len <= n; len++)
	{
		for (int i = 0; i + len - 1 < n; i++)
		{
			int j = i + len - 1;
			if (ispal[i][j])
			{
				int matches = 0;
				for (int k = 0; k < n; k++)
				{
					matches += (lcp[k][i] >= len);
				}
				sol = max(sol, len * matches);
			}
		}
	}
	return sol;
}

struct Vertex
{
	int fail;
	int len;
	vector<int> kids;
	int cnt;
};

vector<Vertex> verts;
vector<int> mt(26, 0);

int smart(string s)
{
	verts.clear();
	verts.push_back({ 0, -1, mt, 0 });
	verts.push_back({ 0, 0,  mt, 0 });
	assert((int)s.size() >= 1);
	s = "$" + s;
	assert((int)s.size() >= 2);
	int n = (int)s.size();
	int curvert = 0;
	for (int i = 1; i < n; i++)
	{
		while (s[i] != s[i - verts[curvert].len - 1])
		{
			assert(curvert >= 1);
			curvert = verts[curvert].fail;
		}
		assert(s[i] == s[i - verts[curvert].len - 1]);
		
		{
			int x = s[i] - 'a';
			assert(0 <= x && x < 26);
			if (!verts[curvert].kids[x])
			{
				int fail = verts[curvert].fail;
				assert(fail >= 0);
				while (s[i] != s[i - verts[fail].len - 1])
				{
					assert(fail >= 1);
					fail = verts[fail].fail;
				}
				
				if (!verts[fail].kids[x])
				{
					assert(fail == 0);
					fail = 1;
				}
				else
				{
					fail = verts[fail].kids[x];
				}
			
				verts.push_back({ fail, verts[curvert].len + 2, mt, 0 });
				
				verts[curvert].kids[x] = (int)verts.size() - 1;
				//cout << (int)verts.size() - 1 << " -> " << fail << "\n";
			}
			curvert = verts[curvert].kids[x];
		}	
		verts[curvert].cnt++;
	}
	vector<int> q = { 0, 1 };
	for (int i = 0; i < (int)q.size(); i++)
	{
		int a = q[i];
		for (int x = 0; x < 26; x++)
		{
			if (verts[a].kids[x])
			{
				q.push_back(verts[a].kids[x]);
			}
		}
	}/*
	for (auto& x : q)
	{
		cout << x << " ";
	}
	cout << "\n";*/
	int sol = 0;
	for (int _ = (int)q.size() - 1; _ >= 0; _--)
	{
		int who = q[_];
		verts[verts[who].fail].cnt += verts[who].cnt;
		sol = max(sol, verts[who].len * verts[who].cnt);
	}
	return sol;
	exit(0);
}

mt19937 rng(228);

int getrng(int l, int r)
{
	assert(l <= r);
	int x = rng() % (r - l + 1) + l;
	assert(l <= x && x <= r);
	return x;
}

string gets(int dim)
{
	dim = getrng(1, dim);
	string s(dim, '?');
	for (auto& ch : s)
	{
		ch = 'a' + getrng(0, 4);
	}
	return s;
}

signed main()
{
#ifdef ONPC	
	FILE* stream;
	freopen_s(&stream, "input.txt", "r", stdin);
#else
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif


	string s;
	cin >> s;
	//cout << dumb(s) << "\n";
	cout << smart(s) << "\n";
	exit(0);
	if (0)
	{
		string s = "aaa";
		cout << smart(s) << "\n";
		cout << dumb(s) << "\n";
		exit(0);
	}

	while (1)
	{
		string s = gets(10);
		if (smart(s) != dumb(s))
		{
			cout << "bad : " << s << "\n";
			cout << "me    : " << smart(s) << "\n";
			cout << "good  : " << dumb(s) << "\n";
			exit(0);
		}
	}


	return 0;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 0 ms 340 KB Output is correct
20 Correct 0 ms 340 KB Output is correct
21 Correct 0 ms 340 KB Output is correct
22 Correct 0 ms 340 KB Output is correct
23 Correct 0 ms 340 KB Output is correct
24 Correct 0 ms 340 KB Output is correct
25 Correct 0 ms 340 KB Output is correct
26 Correct 0 ms 340 KB Output is correct
27 Correct 0 ms 340 KB Output is correct
28 Correct 0 ms 340 KB Output is correct
29 Correct 0 ms 340 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 0 ms 212 KB Output is correct
32 Correct 0 ms 340 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 596 KB Output is correct
2 Correct 1 ms 596 KB Output is correct
3 Correct 1 ms 596 KB Output is correct
4 Correct 1 ms 596 KB Output is correct
5 Correct 1 ms 596 KB Output is correct
6 Correct 1 ms 596 KB Output is correct
7 Correct 0 ms 596 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3212 KB Output is correct
2 Correct 3 ms 3212 KB Output is correct
3 Correct 3 ms 3204 KB Output is correct
4 Correct 3 ms 3204 KB Output is correct
5 Correct 4 ms 3332 KB Output is correct
6 Correct 3 ms 3172 KB Output is correct
7 Correct 3 ms 3204 KB Output is correct
8 Correct 1 ms 464 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 2 ms 2320 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 28928 KB Output is correct
2 Correct 25 ms 29020 KB Output is correct
3 Correct 27 ms 28968 KB Output is correct
4 Correct 23 ms 29052 KB Output is correct
5 Correct 29 ms 29068 KB Output is correct
6 Correct 21 ms 21556 KB Output is correct
7 Correct 23 ms 24832 KB Output is correct
8 Correct 2 ms 852 KB Output is correct
9 Correct 7 ms 7304 KB Output is correct
10 Correct 23 ms 24828 KB Output is correct

Subtask #5
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 77 ms 87332 KB Output is correct
2 Correct 89 ms 87468 KB Output is correct
3 Correct 71 ms 87552 KB Output is correct
4 Correct 70 ms 87536 KB Output is correct
5 Correct 85 ms 87436 KB Output is correct
6 Correct 76 ms 83220 KB Output is correct
7 Correct 84 ms 71532 KB Output is correct
8 Correct 5 ms 1628 KB Output is correct
9 Correct 6 ms 1628 KB Output is correct
10 Correct 76 ms 70404 KB Output is correct
11 Correct 80 ms 87428 KB Output is correct
12 Correct 11 ms 9328 KB Output is correct