Submission #872759

#	Time	Username	Problem	Language	Result	Execution time	Memory
872759		rainboy	Experimental Charges (NOI19_charges)	C11	100 / 100	25 ms	2588 KiB

charges

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

#define N	100000

int ds[N * 2];

int find(int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}

void join(int i, int j) {
	i = find(i);
	j = find(j);
	if (i == j)
		return;
	if (ds[i] > ds[j])
		ds[i] = j;
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i;
	}
}

int main() {
	int n, q;

	scanf("%d%d", &n, &q);
	memset(ds, -1, n * 2 * sizeof *ds);
	while (q--) {
		static char s[2];
		int i, j;

		scanf("%s%d%d", s, &i, &j), i--, j--;
		if (s[0] == 'A')
			join(i << 1 | 0, j << 1 | 1), join(i << 1 | 1, j << 1 | 0);
		else if (s[0] == 'R')
			join(i << 1 | 0, j << 1 | 0), join(i << 1 | 1, j << 1 | 1);
		else
			if (find(i << 1 | 0) == find(j << 1 | 1))
				printf("A\n");
			else if (find(i << 1 | 0) == find(j << 1 | 0))
				printf("R\n");
			else
				printf("?\n");
	}
	return 0;
}

Compilation message (stderr)

charges.c: In function 'main':
charges.c:29:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |  scanf("%d%d", &n, &q);
      |  ^~~~~~~~~~~~~~~~~~~~~
charges.c:35:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |   scanf("%s%d%d", s, &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 14 / 14
• Subtask 4: 12 / 12
• Subtask 5: 25 / 25
• Subtask 6: 31 / 31