oj.uz

Submission #545888

# Submission time Handle Problem Language Result Execution time Memory
545888 2022-04-05T15:54:21 Z rainboy Pipes (CEOI15_pipes) C
40 / 100
 1384 ms 65536 KB 
#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 main() {
	static int ds1[N], ds2[N];
	int n, m, m_, h, i, j;
 
	scanf("%d%d", &n, &m);
	memset(ds1, -1, n * sizeof *ds1);
	memset(ds2, -1, n * sizeof *ds2);
	m_ = 0;
	while (m--) {
		scanf("%d%d", &i, &j), i--, j--;
		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;
}

Compilation message

pipes.c: In function 'main':
pipes.c:61:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
pipes.c:66:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 980 KB Output is correct
2 Correct 3 ms 724 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 139 ms 6264 KB Output is correct
2 Correct 121 ms 5888 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 217 ms 11160 KB Output is correct
2 Correct 250 ms 12452 KB Output is correct

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 362 ms 19512 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 452 ms 30108 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 689 ms 43900 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 883 ms 57036 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1162 ms 65536 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1384 ms 65536 KB Memory limit exceeded
2 Halted 0 ms 0 KB -