oj.uz

Submission #546473

# Submission time Handle Problem Language Result Execution time Memory
546473 2022-04-07T16:09:06 Z rainboy Pipes (CEOI15_pipes) C
100 / 100
 448 ms 13340 KB 
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#define N	100000
#define M	((N - 1) * 2)
 
int min(int a, int b) { return a < b ? a : b; }
 
int ii[M], jj[M]; char bridge[M];
int *eh[N], eo[N];
 
void append(int i, int h) {
	eh[i][eo[i]++] = h;
}
 
int find(int *ds, int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds, ds[i]));
}

int join(int *ds, int i, int j) {
	i = find(ds, i), j = find(ds, j);
	if (i == j)
		return 0;
	if (ds[i] > ds[j])
		ds[i] = j;
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i;
	}
	return 1;
}
 
int ta[N], tb[N];
 
void dfs(int f, int i) {
	static int time;
	int o;
 
	ta[i] = tb[i] = ++time;
	for (o = eo[i]; o--; ) {
		int h = eh[i][o], j = i ^ ii[h] ^ jj[h];
 
		if (h != f) {
			if (!ta[j]) {
				dfs(h, j);
				tb[i] = min(tb[i], tb[j]);
				if (tb[j] == ta[j])
					bridge[h] = 1;
			} else
				tb[i] = min(tb[i], ta[j]);
		}
	}
}
 
int read() {
	char c;
	int a;

	while (!isdigit(c = getchar()))
		;
	a = 0;
	for ( ; isdigit(c); c = getchar())
		a = a * 10 + c - '0';
	return a;
}

int main() {
	static int ds1[N], ds2[N];
	int n, m, m_, h, i, j;
 
	n = read(), m = read();
	memset(ds1, -1, n * sizeof *ds1);
	memset(ds2, -1, n * sizeof *ds2);
	m_ = 0;
	while (m--) {
		i = read() - 1, j = read() - 1;
		if (join(ds1, i, j) || join(ds2, i, j)) {
			ii[m_] = i, jj[m_] = j, m_++;
			eo[i]++, eo[j]++;
		}
	}
	m = m_;
	for (i = 0; i < n; i++)
		eh[i] = (int *) malloc(eo[i] * sizeof *eh[i]), eo[i] = 0;
	for (h = 0; h < m; h++)
		append(ii[h], h), append(jj[h], h);
	for (i = 0; i < n; i++)
		if (!ta[i])
			dfs(-1, i);
	for (h = 0; h < m; h++)
		if (bridge[h])
			printf("%d %d\n", ii[h] + 1, jj[h] + 1);
	return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 852 KB Output is correct
2 Correct 2 ms 724 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 976 KB Output is correct
2 Correct 32 ms 844 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 1736 KB Output is correct
2 Correct 69 ms 1336 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 112 ms 3556 KB Output is correct
2 Correct 90 ms 3484 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 132 ms 9412 KB Output is correct
2 Correct 121 ms 6092 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 204 ms 10992 KB Output is correct
2 Correct 197 ms 8204 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 272 ms 13340 KB Output is correct
2 Correct 282 ms 8736 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 324 ms 13304 KB Output is correct
2 Correct 331 ms 8764 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 448 ms 12556 KB Output is correct
2 Correct 374 ms 10376 KB Output is correct