oj.uz

답안 #63876

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
63876 2018-08-03T06:06:36 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;
        // }
        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 14 ms 14716 KB Output is correct
2 Correct 16 ms 14820 KB Output is correct
3 Correct 17 ms 14880 KB Output is correct
4 Correct 17 ms 14880 KB Output is correct
5 Correct 14 ms 14880 KB Output is correct
6 Correct 14 ms 14880 KB Output is correct
7 Correct 17 ms 14880 KB Output is correct
8 Correct 17 ms 14880 KB Output is correct
9 Correct 15 ms 15000 KB Output is correct
10 Correct 14 ms 15000 KB Output is correct
11 Correct 19 ms 15000 KB Output is correct
12 Correct 18 ms 15000 KB Output is correct
13 Correct 14 ms 15000 KB Output is correct
14 Correct 14 ms 15000 KB Output is correct
15 Correct 15 ms 15076 KB Output is correct
16 Correct 17 ms 15076 KB Output is correct
17 Correct 20 ms 15076 KB Output is correct
18 Correct 15 ms 15076 KB Output is correct
19 Correct 14 ms 15076 KB Output is correct
20 Correct 14 ms 15076 KB Output is correct
21 Correct 13 ms 15076 KB Output is correct
22 Correct 14 ms 15076 KB Output is correct
23 Correct 15 ms 15076 KB Output is correct
24 Correct 15 ms 15076 KB Output is correct
25 Correct 19 ms 15076 KB Output is correct
26 Correct 15 ms 15076 KB Output is correct
27 Correct 13 ms 15076 KB Output is correct
28 Correct 14 ms 15076 KB Output is correct
29 Correct 15 ms 15076 KB Output is correct
30 Correct 16 ms 15076 KB Output is correct
31 Correct 15 ms 15076 KB Output is correct
32 Correct 14 ms 15076 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 20 ms 15356 KB Output is correct
2 Correct 17 ms 15356 KB Output is correct
3 Correct 19 ms 15360 KB Output is correct
4 Correct 19 ms 15360 KB Output is correct
5 Correct 18 ms 15360 KB Output is correct
6 Correct 20 ms 15360 KB Output is correct
7 Correct 21 ms 15360 KB Output is correct
8 Correct 17 ms 15360 KB Output is correct
9 Correct 19 ms 15360 KB Output is correct
10 Correct 17 ms 15360 KB Output is correct
11 Correct 16 ms 15360 KB Output is correct
12 Correct 17 ms 15512 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 33 ms 19452 KB Output is correct
2 Correct 40 ms 19452 KB Output is correct
3 Correct 34 ms 19464 KB Output is correct
4 Correct 40 ms 19464 KB Output is correct
5 Correct 43 ms 19464 KB Output is correct
6 Correct 51 ms 19464 KB Output is correct
7 Correct 36 ms 19464 KB Output is correct
8 Correct 38 ms 19464 KB Output is correct
9 Correct 37 ms 19464 KB Output is correct
10 Correct 34 ms 19464 KB Output is correct

Subtask #4
26.0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 324 ms 60188 KB Output is correct
2 Correct 280 ms 60188 KB Output is correct
3 Correct 361 ms 60468 KB Output is correct
4 Correct 270 ms 61044 KB Output is correct
5 Correct 583 ms 61044 KB Output is correct
6 Correct 373 ms 61044 KB Output is correct
7 Correct 307 ms 61044 KB Output is correct
8 Correct 616 ms 61044 KB Output is correct
9 Correct 564 ms 61044 KB Output is correct
10 Correct 416 ms 61044 KB Output is correct

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1040 ms 132096 KB Time limit exceeded
2 Halted 0 ms 0 KB -