제출 #41974

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
41974		RockyB	회문 (APIO14_palindrome)	C++14	0 / 100	920 ms	2076 KiB

palindrome

/// In The Name Of God

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <bits/stdc++.h>

#define f first
#define s second

#define pb push_back
#define pp pop_back
#define mp make_pair

#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()

#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);

#define nl '\n'
#define ioi exit(0);

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;

const int N = (int)3e5 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;

const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};

using namespace std;


int n;
int p[N];
char s[N];

ll ans;

bool check(int l, int r) {
	int cnt = 0;
	while (l < r && ++cnt <= 100) {
		if (s[l] != s[r]) return 0;
		l++, r--;
	}
	int mid = l + r >> 1;
	for (int i = mid; i >= l; i--) {
		if (s[i] != s[r - i + mid]) return 0;
	}
	return 1;
}
ll get(int len) {
	int mx = 0;
	unordered_map <int, int> cnt;
	for (int i = len; i <= n; i++) {
		int mask = p[i] ^ p[i - len];
		if (__builtin_popcount(mask) > 1) continue;
		if (!check(i - len + 1, i)) continue;
		mx = max(mx, ++cnt[mask]);
	}
	return (ll)mx * len;
}

int main() {
	#ifdef IOI2018
		freopen ("in.txt", "r", stdin);
		freopen ("slow.out", "w", stdout);
	#endif
	Kazakhstan
	cin >> (s + 1);
	n = strlen(s + 1);
	for (int i = 1; i <= n; i++) {
		p[i] = p[i - 1] ^ (1 << (s[i] - 'a'));
	}
	for (int i = 1; i <= n && clock() / (double)CLOCKS_PER_SEC < 0.9; i++) {
		ans = max(ans, get(i));
	}
	cout << ans;
	ioi
}

컴파일 시 표준 에러 (stderr) 메시지

palindrome.cpp: In function 'bool check(int, int)':
palindrome.cpp:51:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid = l + r >> 1;
              ^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27