oj.uz

Submission #473613

# Submission time Handle Problem Language Result Execution time Memory
473613 2021-09-15T17:21:17 Z rainboy Mate (COCI18_mate) C
100 / 100
 562 ms 14556 KB 
#include <stdio.h>
#include <string.h>

#define N	2000
#define A	26
#define MD	1000000007

int vv[N + 1], ff[N + 1], gg[N + 1];

void init() {
	int i;

	ff[0] = gg[0] = 1;
	for (i = 1; i <= N; i++) {
		vv[i] = i == 1 ? 1 : (long long) vv[i - MD % i] * (MD / i + 1) % MD;
		ff[i] = (long long) ff[i - 1] * i % MD;
		gg[i] = (long long) gg[i - 1] * vv[i] % MD;
	}
}

long long choose(int n, int k) {
	return (long long) ff[n] * gg[k] % MD * gg[n - k] % MD;
}

int main() {
	static char cc[N + 1];
	static int kk[A], ans[A][A][N + 1];
	int n, q, i, l, a, b;

	init();
	scanf("%s%d", cc, &q), n = strlen(cc);
	for (i = n - 1; i >= 0; i--) {
		a = cc[i] - 'a';
		for (b = 0; b < A; b++)
			for (l = 0; l <= i + 2; l++)
				ans[a][b][l] = (ans[a][b][l] + choose(i, l - 2) * kk[b]) % MD;
		kk[a]++;
	}
	while (q--) {
		static char s[4];
		int l;

		scanf("%d%s", &l, s);
		printf("%d\n", ans[s[0] - 'a'][s[1] - 'a'][l]);
	}
	return 0;
}

Compilation message

mate.c: In function 'main':
mate.c:31:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |  scanf("%s%d", cc, &q), n = strlen(cc);
      |  ^~~~~~~~~~~~~~~~~~~~~
mate.c:43:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |   scanf("%d%s", &l, s);
      |   ^~~~~~~~~~~~~~~~~~~~

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 3148 KB Output is correct
2 Correct 6 ms 2764 KB Output is correct
3 Correct 10 ms 2892 KB Output is correct
4 Correct 15 ms 2956 KB Output is correct
5 Correct 58 ms 4692 KB Output is correct
6 Correct 45 ms 4828 KB Output is correct
7 Correct 36 ms 4676 KB Output is correct
8 Correct 35 ms 4548 KB Output is correct
9 Correct 555 ms 14556 KB Output is correct
10 Correct 562 ms 14480 KB Output is correct