Submission #486427

#	Time	Username	Problem	Language	Result	Execution time	Memory
486427		rainboy	Palinilap (COI16_palinilap)	C11	54 / 100	1078 ms	22224 KiB

palinilap

#include <stdio.h>
#include <string.h>

#define N	100000
#define A	26

long long max(long long a, long long b) { return a > b ? a : b; }

int main() {
	static long long kk[N + 1][A], ll[N + 1], mm[N + 1];
	static char cc[N + 1];
	int n, h, i, j, i_, j_, ij, a;
	long long k_;

	scanf("%s", cc), n = strlen(cc);
	for (ij = 0; ij <= n - 1 + n - 1; ij++)
		for (i = ij / 2, j = ij - i, i_ = j_ = -1; i >= 0 && j < n; i--, j++) {
			if (cc[i] != cc[j]) {
				if (i_ == -1)
					i_ = i, j_ = j;
				else
					break;
			}
			if (i_ == -1) {
				if (ij % 2 == 0) {
					h = ij / 2;
					mm[i]++, mm[h]--, ll[h]++, ll[h + 1]--, mm[h + 1]++, mm[j + 1]--;
				} else
					mm[i]++, mm[j + 1]--;
				ll[0]++, ll[i]--, ll[j + 1]++, ll[n]--;
			} else
				kk[i_][cc[j_] - 'a']++, kk[j_][cc[i_] - 'a']++;
		}
	for (i = 1; i < n; i++)
		ll[i] += ll[i - 1];
	for (i = 1; i < n; i++)
		mm[i] += mm[i - 1];
	k_ = 0;
	for (i = 0; i < n; i++)
		for (a = 0; a < A; a++)
			k_ = max(k_, kk[i][a] + ll[i] + (cc[i] == a + 'a' ? mm[i] : 0));
	printf("%lld\n", k_);
	return 0;
}

Compilation message (stderr)

palinilap.c: In function 'main':
palinilap.c:15:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |  scanf("%s", cc), n = strlen(cc);
      |  ^~~~~~~~~~~~~~~

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