Submission #730954

#	Time	Username	Problem	Language	Result	Execution time	Memory
730954		rainboy	Monthly railway pass (LMIO18_menesinis_bilietas)	C11	100 / 100	169 ms	32780 KiB

menesinis_bilietas

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

#define N	500000
#define M	500000

int ds[N], sz[N];

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, sz[j] += sz[i];
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i, sz[i] += sz[j];
	}
}

int *ej[N], eo[N];

void append(int i, int j) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
	ej[i][o] = j;
}

int main() {
	static int ii[M], jj[M];
	static char tt[M], used[N];
	int n, m, h, i, j, o, c, k, s;

	scanf("%d%d", &n, &m);
	memset(ds, -1, n * sizeof *ds);
	for (i = 0; i < n; i++)
		sz[i] = 1;
	for (h = 0; h < m; h++) {
		static char s[2];

		scanf("%d%d%s", &i, &j, s), i--, j--;
		ii[h] = i, jj[h] = j, tt[h] = s[0];
		if (tt[h] == 'T')
			join(i, j);
	}
	c = 0;
	for (i = 0; i < n; i++)
		if (ds[i] < 0) {
			ej[i] = (int *) malloc(2 * sizeof *ej[i]);
			c++;
		}
	for (h = 0; h < m; h++)
		if (tt[h] == 'A') {
			i = find(ii[h]), j = find(jj[h]);
			if (i != j)
				append(i, j), append(j, i);
		}
	s = 0;
	for (i = 0; i < n; i++)
		if (ds[i] < 0) {
			k = 0;
			for (o = eo[i]; o--; ) {
				j = ej[i][o];
				if (!used[j])
					used[j] = 1, k++;
			}
			if (k == c - 1)
				s += sz[i];
			for (o = eo[i]; o--; ) {
				j = ej[i][o];
				used[j] = 0;
			}
		}
	printf("%d\n", s);
	return 0;
}

Compilation message (stderr)

menesinis_bilietas.c: In function 'append':
menesinis_bilietas.c:33:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   33 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
menesinis_bilietas.c: In function 'main':
menesinis_bilietas.c:43:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
menesinis_bilietas.c:50:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |   scanf("%d%d%s", &i, &j, s), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 6 / 6
• Subtask 3: 30 / 30
• Subtask 4: 35 / 35
• Subtask 5: 19 / 19