oj.uz

답안 #63868

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
63868 2018-08-03T05:42:17 Z qkxwsm 회문 (APIO14_palindrome) C++17
23 / 100
 1000 ms 108856 KB 
/*
PROG: source
LANG: C++11
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
        int operator()(int x) const
        {
                x ^= (x >> 20) ^ (x >> 12);
                return x ^ (x >> 7) ^ (x >> 4);
        }
        int operator()(long long x) const
        {
                return x ^ (x >> 32);
        }
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using hashtable = gp_hash_table<T, U, chash>;

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
        {
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
template<class T, class U>
T normalize(T x, U mod = 1000000007)
{
	return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
	return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
	return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 300013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N;
int s[MAXN], t[2 * MAXN];
int len[2 * MAXN];
vector<int> sse[MAXN], sfi[MAXN];
int suf[MAXN], srank[MAXN], lcp[MAXN];
int sparse[25][MAXN];
int sval[25][MAXN];
ll ans = 0;

void manacher()
{
        int lt = 0, rt = 0;
        for (int i = 0; i <= 2 * N; i++)
        {
                len[i] = min(rt - i, len[lt + (rt - i)]);
                while(0 <= i - len[i] && i + len[i] <= 2 * N && t[i - len[i]] == t[i + len[i]])
                {
                        len[i]++;
                }
                if (i + len[i] > rt)
                {
                        lt = i - len[i];
                        rt = i + len[i];
                }
                len[i]--;
        }
        return;
}
void buildsuf()
{
        for (int i = 0; i < N; i++)
        {
                sval[0][i] = s[i];
        }
        for (int i = 0; i < 20; i++)
        {
                int Z = max(30, N);
                for (int j = 0; j <= Z; j++)
                {
                        sse[j].clear();
                        sfi[j].clear();
                }
                for (int j = 0; j < N; j++)
                {
                        int val1 = (((j + (1 << i)) >= N) ? 0 : sval[i][j + (1 << i)]);
                        sse[val1].PB(j);
                }
                for (int j = 0; j <= Z; j++)
                {
                        for (int idx : sse[j])
                        {
                                int val = sval[i][idx];
                                sfi[val].PB(idx);
                        }
                }
                pii was = {-1, -1}; int K = 0;
                for (int j = 0; j <= Z; j++)
                {
                        for (int idx : sfi[j])
                        {
                                pii cur = {sval[i][idx], ((idx + (1 << i)) >= N ? 0 : sval[i][idx + (1 << i)])};
                                if (cur > was)
                                {
                                        K++;
                                        was = cur;
                                }
                                sval[i + 1][idx] = K;
                        }
                }
        }
        for (int i = 0; i < N; i++)
        {
                srank[i] = sval[20][i] - 1;
                suf[srank[i]] = i;
        }
        int best = 0;
        for (int i = 0; i < N; i++)
        {
                int idx = srank[i];
                if (idx == N - 1)
                {
                        lcp[idx] = 0;
                        continue;
                }
                int j = suf[idx + 1];
                while(i + best < N && j + best < N && s[i + best] == s[j + best]) best++;
                lcp[idx] = best;
                if (best) best--;
        }
}
int query(int lt, int rt)
{
        int lg = 31 - __builtin_clz(rt - lt + 1);
        int res = min(sparse[lg][lt], sparse[lg][rt - (1 << lg) + 1]);
        return res;
}
int chk(int lt, int rt)
{
        int sz = rt - lt + 1, res = 1, cur = srank[lt], lo, hi;
        // cerr << "count " << lt << ' ' << rt << endl;
        lo = 0, hi = cur;
        while(hi > lo)
        {
                int mid = (hi + lo) / 2;
                if (query(mid, cur - 1) < sz)
                {
                        lo = mid + 1;
                }
                else
                {
                        hi = mid;
                }
        }
        res += (cur - lo);
        // cerr << "res " << res << endl;
        return res;
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	srand(time(0));
	//	cout << fixed << setprecision(10);
	//	cerr << fixed << setprecision(10);
	if (fopen("input.in", "r"))
	{
		freopen ("input.in", "r", stdin);
		freopen ("output.out", "w", stdout);
	}
        string temps; cin >> temps;
        N = temps.length();
        for (int i = 0; i < N; i++)
        {
                s[i] = temps[i] - 'a' + 1;
        }
        for (int i = 0; i < N; i++)
        {
                t[2 * i + 1] = s[i];
        }
        manacher();
        // for (int i = 0; i <= 2 * N; i++)
        // {
        //         cerr << t[i] << ' ';
        // }
        // cerr << endl;
        // for (int i = 0; i <= 2 * N; i++)
        // {
        //         cerr << len[i] << ' ';
        // }
        // cerr << endl;
        buildsuf();
        for (int i = 0; i < N - 1; i++)
        {
                sparse[0][i] = lcp[i];
        }
        for (int i = 1; i < 20; i++)
        {
                for (int j = 0; j < N - 1; j++)
                {
                        sparse[i][j] = min(sparse[i - 1][j], ((j + (1 << (i - 1)) < N - 1) ? sparse[i - 1][j + (1 << (i - 1))] : 0));
                }
        }
        // for (int i = 0; i < N; i++)
        // {
        //         cerr << suf[i] << endl;
        // }
        for (int i = 1; i < 2 * N; i++)
        {
                int lt, rt;
                if (i % 2)
                {
                        lt = (i / 2) - (len[i] / 2);
                        rt = (i / 2) + (len[i] / 2);
                }
                else
                {
                        lt = (i / 2) - (len[i] / 2);
                        rt = (i / 2) + (len[i] / 2) - 1;
                }
                if (lt > rt)
                {
                        continue;
                }
                int counter = 0;
                while(lt <= rt)
                {
                        ckmax(ans, 1ll * (rt - lt + 1) * chk(lt, rt));
                        lt++; rt--;
                }
                // cerr << lt << ' ' << rt << endl;
        }
        // for (int i = 0; i <= 2 * N; i++)
        // {
        //         cerr << len[i] << ' ';
        // }
        // cerr << endl;
        cout << ans << '\n';
	//	cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Compilation message

palindrome.cpp: In function 'int32_t main()':
palindrome.cpp:326:21: warning: unused variable 'counter' [-Wunused-variable]
                 int counter = 0;
                     ^~~~~~~
palindrome.cpp:269:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("input.in", "r", stdin);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:270:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("output.out", "w", stdout);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 14712 KB Output is correct
2 Correct 17 ms 14712 KB Output is correct
3 Correct 15 ms 14856 KB Output is correct
4 Correct 15 ms 14856 KB Output is correct
5 Correct 15 ms 15016 KB Output is correct
6 Correct 16 ms 15016 KB Output is correct
7 Correct 17 ms 15016 KB Output is correct
8 Correct 18 ms 15016 KB Output is correct
9 Correct 17 ms 15016 KB Output is correct
10 Correct 14 ms 15016 KB Output is correct
11 Correct 16 ms 15016 KB Output is correct
12 Correct 17 ms 15016 KB Output is correct
13 Correct 14 ms 15016 KB Output is correct
14 Correct 14 ms 15016 KB Output is correct
15 Correct 17 ms 15016 KB Output is correct
16 Correct 17 ms 15016 KB Output is correct
17 Correct 15 ms 15016 KB Output is correct
18 Correct 16 ms 15016 KB Output is correct
19 Correct 16 ms 15016 KB Output is correct
20 Correct 19 ms 15016 KB Output is correct
21 Correct 19 ms 15016 KB Output is correct
22 Correct 14 ms 15016 KB Output is correct
23 Correct 19 ms 15080 KB Output is correct
24 Correct 17 ms 15080 KB Output is correct
25 Correct 20 ms 15080 KB Output is correct
26 Correct 14 ms 15080 KB Output is correct
27 Correct 15 ms 15080 KB Output is correct
28 Correct 19 ms 15080 KB Output is correct
29 Correct 17 ms 15084 KB Output is correct
30 Correct 18 ms 15084 KB Output is correct
31 Correct 15 ms 15084 KB Output is correct
32 Correct 15 ms 15084 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 46 ms 15212 KB Output is correct
2 Correct 25 ms 15340 KB Output is correct
3 Correct 60 ms 15340 KB Output is correct
4 Correct 17 ms 15340 KB Output is correct
5 Correct 72 ms 15340 KB Output is correct
6 Correct 63 ms 15340 KB Output is correct
7 Correct 17 ms 15340 KB Output is correct
8 Correct 41 ms 15440 KB Output is correct
9 Correct 20 ms 15440 KB Output is correct
10 Correct 19 ms 15440 KB Output is correct
11 Correct 16 ms 15440 KB Output is correct
12 Correct 17 ms 15440 KB Output is correct

Subtask #3
0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1064 ms 18556 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1080 ms 50696 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1075 ms 108856 KB Time limit exceeded
2 Halted 0 ms 0 KB -