제출 #240657

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
240657		BorisBarca	Palinilap (COI16_palinilap)	C++14	0 / 100	118 ms	13944 KiB

palinilap

/*
$$$$$$$\                      $$\           $$$$$$$\
$$  __$$\                     \__|          $$  __$$\
$$ |  $$ | $$$$$$\   $$$$$$\  $$\  $$$$$$$\ $$ |  $$ | $$$$$$\   $$$$$$\   $$$$$$$\ $$$$$$\
$$$$$$$\ |$$  __$$\ $$  __$$\ $$ |$$  _____|$$$$$$$\ | \____$$\ $$  __$$\ $$  _____|\____$$\
$$  __$$\ $$ /  $$ |$$ |  \__|$$ |\$$$$$$\  $$  __$$\  $$$$$$$ |$$ |  \__|$$ /      $$$$$$$ |
$$ |  $$ |$$ |  $$ |$$ |      $$ | \____$$\ $$ |  $$ |$$  __$$ |$$ |      $$ |     $$  __$$ |
$$$$$$$  |\$$$$$$  |$$ |      $$ |$$$$$$$  |$$$$$$$  |\$$$$$$$ |$$ |      \$$$$$$$\\$$$$$$$ |
\_______/  \______/ \__|      \__|\_______/ \_______/  \_______|\__|       \_______|\_______|
*/
#include <bits/stdc++.h>

using namespace std;

#define PB push_back
#define MP make_pair
#define INS insert
#define LB lower_bound
#define UB upper_bound
#define pii pair <int,int>
#define pll pair <long long, long long>
#define X first
#define Y second
#define _ << " " <<
#define sz(x) (int)x.size()
#define all(a) (a).begin(),(a).end()
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORD(i, a, b) for (int i = (a); i > (b); --i)
#define FORA(i, x) for (auto &i : x)
#define REP(i, n) FOR(i, 0, n)
#define BITS(x) __builtin_popcount(x)
#define SQ(a) (a) * (a)
#define TRACE(x) cout << #x " = " << (x) << '\n';
#define YES cout << "YES\n"
#define NO cout << "NO\n"
#define umap unordered_map

typedef long long ll;
typedef long double ld;
typedef vector <int> vi;
typedef vector <pii> vpi;
typedef vector <ll> vll;
typedef vector <pll> vpl;
typedef vector <double> vd;
typedef vector <ld> vld;
typedef vector<string> vs;
//((float) t)/CLOCKS_PER_SEC

const int MOD = 1e9 + 2015;
const double PI = acos(-1);
const int INF = 1e9 + 10;
const ll INFL = 1e18 + 10;
const int ABC = 30;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int dox[] = {-1, 1, 0, 0, -1, -1, 1, 1};
const int doy[] = {0, 0, -1, 1, -1, 1, -1, 1};

inline int sum(int a, int b){
	if (a + b < 0)
		return (a + b + MOD) % MOD;
	return (a + b) % MOD;
}

inline void add(int &a, int b){
	a = sum(a, b);
}

inline int mul(int a, int b){
	return (ll)a * (ll)b % MOD;
}

inline int sub(int a, int b){
	return (a - b + MOD) % MOD;
}

inline int fast_pot(ll pot, ll n){
	ll ret = 1;
	while (n){
		if (n & 1LL)
			ret = (ret * pot) % MOD;
		pot = (pot * pot) % MOD;
		n >>= 1LL;
	}
	return ret;
}

inline int divide(int a, int b){
	return mul(a, fast_pot(b, MOD - 2));
}

ll lcm(ll a, ll b){
	return abs(a * b) / __gcd(a, b);
}

inline double ccw(pii A, pii B, pii C){
	return (A.X * B.Y) - (A.Y * B.X) + (B.X * C.Y) - (B.Y * C.X) + (C.X * A.Y) - (C.Y * A.X);
}

inline int CCW(pii A, pii B, pii C){
	double val = ccw(A, B, C);
	double eps = max(max(abs(A.X), abs(A.Y)), max(max(abs(B.X), abs(B.Y)), max(abs(C.X), abs(C.Y)))) / 1e9;
	if (val <= -eps)
		return -1;
	if (val >= eps)
		return 1;
	return 0;
}

void to_upper(string &x){
	REP(i, sz(x))
		x[i] = toupper(x[i]);
}

void to_lower(string &x){
	REP(i, sz(x))
		x[i] = tolower(x[i]);
}

string its(ll x){
	if (x == 0)
		return "0";
	string ret = "";
	while (x > 0){
		ret += (x % 10) + '0';
		x /= 10;
	}
	reverse(all(ret));
	return ret;
}

ll sti(string s){
	ll ret = 0;
	REP(i, sz(s)){
		ret *= 10;
		ret += (s[i] - '0');
	}
	return ret;
}

const int N = 1e5 + 10;
const int P = 31;

string s;
int n, sol[N][ABC], h[2][N], pot[N], destroy[N];

int get_hash(int f, int i, int l){
	if (l == 0)
		return 0;
	return sub(h[f][i + l - 1], (i ? mul(h[f][i - 1], pot[l]) : 0));
}

int palin(int i, int l){
	return get_hash(0, i, l) == get_hash(1, n - i - l, l); 
}

int main () {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	cin >> s;
	n = sz(s);
	if (n == 1){
		cout << 1 << '\n';
		return 0;
	}

	h[0][0] = s[0] - 'a' + 1;
	h[1][0] = s[n - 1] - 'a' + 1;
	pot[0] = 1;

	FOR(i, 1, n){
		h[0][i] = mul(h[0][i - 1], P);
		h[1][i] = mul(h[1][i - 1], P);
		add(h[0][i], s[i] - 'a' + 1);
		add(h[1][i], s[n - i - 1] - 'a' + 1);
		pot[i] = mul(P, pot[i - 1]);
	}

	//provjeri neparne
	ll ans = n;
	FOR(i, 1, n - 1){

		int lo = 0, hi = min(i, n - i - 1);
		while (lo < hi){
			int mid = (lo + hi + 1) / 2;
			if (palin(i - mid, mid * 2 + 1))
				lo = mid;
			else
				hi = mid - 1;
		}

		int cnt = lo;
		FORD(j, i - 1, i - lo - 1){
			destroy[j] -= cnt;
			cnt--;
		}
		cnt = lo;
		FOR(j, i + 1, i + lo + 1){
			destroy[j] -= cnt;
			cnt--;
		}

		ans += lo;

		int l = i - lo - 1;
		if (l < 0)
			continue;
		int r = i + lo + 1;
		if (r >= n)
			continue;
		l--;
		r++;
		if (l < 0 || r > n){
			l++;
			r--;
			if (l < 0 || r >= n)
				continue;
			sol[l][s[r] - 'a']++;
			sol[r][s[l] - 'a']++;
			continue;
		}

		lo = 0, hi = min(l + 1, n - r);
		while (lo < hi){
			int mid = (lo + hi + 1) / 2;
			//cout << mid << '\n';
			if (get_hash(1, n - l - 1, mid) == get_hash(0, r, mid))
				lo = mid;
			else
				hi = mid - 1;
		}

		sol[l + 1][s[r - 1] - 'a'] += lo + 1;
		sol[r - 1][s[l + 1] - 'a'] += lo + 1;
	}

	//provjeri parne
	REP(i, n - 1){

		int lo = 1, hi = min(i, n - i) + 1;
		while (lo < hi){
			int mid = (lo + hi + 1) / 2;
			if (palin(i - mid + 1, mid * 2))
				lo = mid;
			else
				hi = mid - 1;
		}

		if (s[i] == s[i + 1]){
			int cnt = lo;
			FORD(j, i, i - lo){
				destroy[j] -= cnt;
				cnt--;
			}
			cnt = lo;
			FOR(j, i + 1, i + lo + 1){
				destroy[j] -= cnt;
				cnt--;
			}
			ans += lo;
		}

		int l, r;
		if (s[i] == s[i + 1]){
			l = i - lo - 1;
			if (l < 0)
				continue;
			r = i + lo + 1;
			if (r >= n)
				continue;
			l--;
			r++;
		} else {
			l = i - 1;
			r = i + 2;
			lo = 0;
		}


		if (l < 0 || r >= n){
			l++;
			r--;
			if (l < 0 || r >= n)
				continue;
			sol[l][s[r] - 'a']++;
			sol[r][s[l] - 'a']++;
			continue;
		}

		lo = 0, hi = min(l + 1, n - r);
		while (lo < hi){
			int mid = (lo + hi + 1) / 2;
			//cout << mid << '\n';
			if (get_hash(1, n - l - 1, mid) == get_hash(0, r, mid))
				lo = mid;
			else
				hi = mid - 1;
		}

		sol[l + 1][s[r - 1] - 'a'] += lo + 1;
		sol[r - 1][s[l + 1] - 'a'] += lo + 1;
	}

	//cout << ans << '\n';

	ll w = ans;
	REP(i, n)
		REP(j, ABC)
			w = max(w, ans + sol[i][j] + (j != s[i] - 'a' ? 1 : 0) * destroy[i]);

	cout << w << '\n';
	
	return 0;
}

• Subtask 1: 0 / 17
• Subtask 2: 0 / 37
• Subtask 3: 0 / 46