Submission #781182

#	Time	Username	Problem	Language	Result	Execution time	Memory
781182		rainboy	Povjerenstvo (COI22_povjerenstvo)	C11	100 / 100	402 ms	95692 KiB

Main

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

#define N	500000
#define M	500000

int *ej[N], eo[N], *fi[N], fo[N], rr[N], qu[N], qu_[N], ii_[N], cnt;

void append(int **ej, int *eo, 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;
}

void dfs1(int i) {
	int o;

	if (rr[i])
		return;
	rr[i] = -1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		dfs1(j);
	}
	qu[--cnt] = i;
}

void dfs2(int j, int r) {
	int o;

	if (rr[j] != -1)
		return;
	qu_[cnt++] = j;
	rr[j] = r;
	for (o = fo[j]; o--; ) {
		int i = fi[j][o];

		dfs2(i, r);
	}
}

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 cc[N]; char done[N];

void mark(int j, int c) {
	int o;

	if (done[j])
		return;
	cc[j] = c, done[j] = 1;
	if (c == 0) {
		for (o = fo[j]; o--; ) {
			int i = fi[j][o];

			if (!done[i] && --eo[i] == 0)
				ii_[cnt++] = i;
		}
	} else {
		for (o = fo[j]; o--; ) {
			int i = fi[j][o];

			mark(i, 0);
		}
	}
}

int main() {
	static int ii[M], jj[M];
	int n, m, h, h_, h1, i, j;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++) {
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
		fi[i] = (int *) malloc(2 * sizeof *fi[i]);
	}
	for (h = 0; h < m; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		ii[h] = i, jj[h] = j;
		append(ej, eo, i, j), append(fi, fo, j, i);
	}
	cnt = n;
	for (i = 0; i < n; i++)
		dfs1(i);
	cnt = 0;
	for (h = 0; h < n; h++) {
		i = qu[h];
		dfs2(i, i);
	}
	memset(ds, -1, n * 2 * sizeof *ds);
	for (h = 0; h < m; h++) {
		i = ii[h], j = jj[h];
		if (rr[i] == rr[j])
			join(i << 1 | 0, j << 1 | 1), join(j << 1 | 0, i << 1 | 1);
	}
	for (i = 0; i < n; i++)
		cc[i] = find(i << 1 | 0) < find(i << 1 | 1) ? 0 : 1;
	cnt = 0;
	for (i = 0; i < n; i++)
		if (eo[i] == 0)
			ii_[cnt++] = i;
	for (h = n - 1; h >= 0; h = h_) {
		while (cnt)
			mark(ii_[--cnt], 1);
		h_ = h - 1;
		while (h_ >= 0 && rr[qu_[h_]] == rr[qu_[h]])
			h_--;
		for (h1 = h; h1 > h_; h1--)
			mark(qu_[h1], cc[qu_[h1]]);
	}
	cnt = 0;
	for (i = 0; i < n; i++)
		if (cc[i])
			ii_[cnt++] = i;
	printf("%d\n", cnt);
	while (cnt--)
		printf("%d ", ii_[cnt] + 1);
	printf("\n");
	return 0;
}

Compilation message (stderr)

Main.c: In function 'append':
Main.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
Main.c: In function 'main':
Main.c:94:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
Main.c:100:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 21 / 21
• Subtask 3: 33 / 33
• Subtask 4: 33 / 33