Submission #745312

#	Time	Username	Problem	Language	Result	Execution time	Memory
745312		rainboy	Fountain (eJOI20_fountain)	C11	100 / 100	346 ms	20724 KiB

fountain

#include <stdio.h>

#define N	100000
#define L	17	/* L = ceil(log2(N)) */

int main() {
	static int dd[N], cc[N], qu[N], pp[L + 1][N + 1], ss[L + 1][N + 1];
	int n, q, cnt, i, l, s;

	scanf("%d%d", &n, &q);
	for (i = 0; i < n; i++)
		scanf("%d%d", &dd[i], &cc[i]);
	pp[0][n] = n, ss[0][n] = 0;
	cnt = 0;
	for (i = n - 1; i >= 0; i--) {
		while (cnt && dd[qu[cnt - 1]] <= dd[i])
			cnt--;
		pp[0][i] = cnt == 0 ? n : qu[cnt - 1], ss[0][i] = cc[i];
		qu[cnt++] = i;
	}
	for (l = 0; l < L; l++)
		for (i = 0; i <= n; i++) {
			pp[l + 1][i] = pp[l][pp[l][i]];
			ss[l + 1][i] = ss[l][i] + ss[l][pp[l][i]];
		}
	while (q--) {
		scanf("%d%d", &i, &s), i--;
		if (s > ss[L][i]) {
			printf("0\n");
			continue;
		}
		for (l = L; l >= 0; l--)
			if (s > ss[l][i])
				s -= ss[l][i], i = pp[l][i];
		printf("%d\n", i + 1);
	}
	return 0;
}

Compilation message (stderr)

fountain.c: In function 'main':
fountain.c:10:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |  scanf("%d%d", &n, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~
fountain.c:12:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |   scanf("%d%d", &dd[i], &cc[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fountain.c:27:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |   scanf("%d%d", &i, &s), i--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40