oj.uz

답안 #63881

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
63881 2018-08-03T06:09:36 Z qkxwsm 회문 (APIO14_palindrome) C++17
73 / 100
 1000 ms 132096 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];
pll shash[MAXN], pw[MAXN];
set<pll> vis;
ll ans = 0;

pll srange(int L, int R)
{
	pll res;
	res.fi = normalize(shash[R + 1].fi - shash[L].fi * pw[R - L + 1].fi, INF);
	res.se = normalize(shash[R + 1].se - shash[L].se * pw[R - L + 1].se, BIG);
	return res;
}

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);
        lo = cur - 1, hi = N - 2;
        while(hi > lo)
        {
                int mid = (hi + lo + 1) / 2;
                if (query(cur, mid) < sz)
                {
                        hi = mid - 1;
                }
                else
                {
                        lo = mid;
                }
        }
        res += (lo - cur + 1);
        // 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++)
        {
                shash[i + 1].fi = shash[i].fi * CO + s[i]; shash[i + 1].fi %= INF;
                shash[i + 1].se = shash[i].se * CO + s[i]; shash[i + 1].se %= BIG;
        }
        pw[0] = {1, 1};
        for (int i = 0; i < N; i++)
        {
                pw[i + 1].fi = pw[i].fi * CO; pw[i + 1].fi %= INF;
                pw[i + 1].se = pw[i].se * CO; pw[i + 1].se %= BIG;
        }
        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;
        // }
        assert(N <= 100000);
        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;
                }
                while(lt <= rt && vis.find(srange(lt, rt)) == vis.end())
                {
                        ckmax(ans, 1ll * (rt - lt + 1) * chk(lt, rt));
                        vis.insert(srange(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:294:11: 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:295:11: 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 18 ms 14840 KB Output is correct
2 Correct 15 ms 14840 KB Output is correct
3 Correct 15 ms 14840 KB Output is correct
4 Correct 13 ms 14840 KB Output is correct
5 Correct 18 ms 14840 KB Output is correct
6 Correct 14 ms 15004 KB Output is correct
7 Correct 14 ms 15004 KB Output is correct
8 Correct 14 ms 15004 KB Output is correct
9 Correct 14 ms 15004 KB Output is correct
10 Correct 20 ms 15004 KB Output is correct
11 Correct 19 ms 15004 KB Output is correct
12 Correct 18 ms 15004 KB Output is correct
13 Correct 14 ms 15004 KB Output is correct
14 Correct 17 ms 15004 KB Output is correct
15 Correct 15 ms 15004 KB Output is correct
16 Correct 15 ms 15004 KB Output is correct
17 Correct 15 ms 15004 KB Output is correct
18 Correct 15 ms 15004 KB Output is correct
19 Correct 15 ms 15048 KB Output is correct
20 Correct 14 ms 15048 KB Output is correct
21 Correct 15 ms 15048 KB Output is correct
22 Correct 15 ms 15048 KB Output is correct
23 Correct 14 ms 15048 KB Output is correct
24 Correct 20 ms 15048 KB Output is correct
25 Correct 18 ms 15048 KB Output is correct
26 Correct 14 ms 15048 KB Output is correct
27 Correct 18 ms 15048 KB Output is correct
28 Correct 18 ms 15048 KB Output is correct
29 Correct 20 ms 15048 KB Output is correct
30 Correct 21 ms 15048 KB Output is correct
31 Correct 17 ms 15048 KB Output is correct
32 Correct 17 ms 15048 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 15340 KB Output is correct
2 Correct 18 ms 15340 KB Output is correct
3 Correct 15 ms 15468 KB Output is correct
4 Correct 17 ms 15468 KB Output is correct
5 Correct 15 ms 15468 KB Output is correct
6 Correct 15 ms 15468 KB Output is correct
7 Correct 19 ms 15480 KB Output is correct
8 Correct 16 ms 15480 KB Output is correct
9 Correct 15 ms 15480 KB Output is correct
10 Correct 20 ms 15480 KB Output is correct
11 Correct 19 ms 15480 KB Output is correct
12 Correct 20 ms 15480 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 30 ms 19452 KB Output is correct
2 Correct 43 ms 19452 KB Output is correct
3 Correct 42 ms 19452 KB Output is correct
4 Correct 38 ms 19452 KB Output is correct
5 Correct 40 ms 19452 KB Output is correct
6 Correct 44 ms 19452 KB Output is correct
7 Correct 39 ms 19452 KB Output is correct
8 Correct 36 ms 19452 KB Output is correct
9 Correct 42 ms 19452 KB Output is correct
10 Correct 47 ms 19452 KB Output is correct

Subtask #4
26.0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 346 ms 60188 KB Output is correct
2 Correct 368 ms 60188 KB Output is correct
3 Correct 313 ms 60640 KB Output is correct
4 Correct 391 ms 61120 KB Output is correct
5 Correct 641 ms 61120 KB Output is correct
6 Correct 392 ms 61120 KB Output is correct
7 Correct 375 ms 61120 KB Output is correct
8 Correct 747 ms 61120 KB Output is correct
9 Correct 565 ms 61120 KB Output is correct
10 Correct 474 ms 61120 KB Output is correct

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1025 ms 132096 KB Time limit exceeded
2 Halted 0 ms 0 KB -