CSES - Datatähti Open 2017 - Results
Submission details
Task:Tunnels
Sender:ulna
Submission time:2017-01-21 11:14:47 +0200
Language:C++
Status:READY
Result:100
Feedback
groupverdictscore
#1ACCEPTED16
#2ACCEPTED31
#3ACCEPTED53
Test results
testverdicttimegroup
#1ACCEPTED0.04 s1details
#2ACCEPTED0.05 s1details
#3ACCEPTED0.04 s1details
#4ACCEPTED0.05 s1details
#5ACCEPTED0.06 s1details
#6ACCEPTED0.04 s2details
#7ACCEPTED0.05 s2details
#8ACCEPTED0.04 s2details
#9ACCEPTED0.04 s2details
#10ACCEPTED0.04 s2details
#11ACCEPTED0.13 s3details
#12ACCEPTED0.11 s3details
#13ACCEPTED0.06 s3details
#14ACCEPTED0.07 s3details
#15ACCEPTED0.05 s3details

Compiler report

input/code.cpp: In function 'int main()':
input/code.cpp:28:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
                        ^
input/code.cpp:32:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &x, &y);
                         ^

Code

#include <bits/stdc++.h>
using namespace std;

// why am I so weak

int n, m;
bool used[100055];
vector<int> g[100055], vs;

void dfs(int v) {
	if (used[v]) return;

	used[v] = true;

	for (auto u : g[v]) {
		dfs(u);
	}

	vs.push_back(v);
}
void rdfs(int v) {
	if (g[v].empty()) return;

	rdfs(g[v].back());
	g[v].pop_back();
}
int main() {
	scanf("%d %d", &n, &m);

	while (m--) {
		int x, y;
		scanf("%d %d", &x, &y);
		x--, y--;

		g[x].push_back(y);
	}

	for (int i = 0; i < n; i++) if (!used[i]) {
		dfs(i);
	}


	int res = 0;

	for (int i = n - 1; i >= 0; i--) {
		int v = vs[i];
		while (!g[v].empty()) {
			res++;
			rdfs(g[v].back());
			g[v].pop_back();
		}
	}

	cout << res << endl;

	return 0;
}

Test details

Test 1

Group: 1

Verdict: ACCEPTED

input
10 20
4 5
6 4
5 1
5 9
...

correct output
11

user output
11

Test 2

Group: 1

Verdict: ACCEPTED

input
10 10
7 3
5 2
9 7
1 5
...

correct output
5

user output
5

Test 3

Group: 1

Verdict: ACCEPTED

input
10 5
5 7
3 8
5 8
3 7
...

correct output
4

user output
4

Test 4

Group: 1

Verdict: ACCEPTED

input
10 4
9 1
6 8
7 1
5 7

correct output
3

user output
3

Test 5

Group: 1

Verdict: ACCEPTED

input
10 2
10 6
2 1

correct output
2

user output
2

Test 6

Group: 2

Verdict: ACCEPTED

input
100 200
24 40
25 6
36 93
92 90
...

correct output
97

user output
97

Test 7

Group: 2

Verdict: ACCEPTED

input
100 100
98 37
91 37
60 92
46 27
...

correct output
60

user output
60

Test 8

Group: 2

Verdict: ACCEPTED

input
100 50
74 95
53 72
69 85
14 13
...

correct output
34

user output
34

Test 9

Group: 2

Verdict: ACCEPTED

input
100 40
28 76
10 81
13 52
46 83
...

correct output
29

user output
29

Test 10

Group: 2

Verdict: ACCEPTED

input
100 20
27 35
72 92
56 4
64 80
...

correct output
18

user output
18

Test 11

Group: 3

Verdict: ACCEPTED

input
100000 200000
89244 59358
22943 56710
63331 89437
56581 38400
...

correct output
102510

user output
102510

Test 12

Group: 3

Verdict: ACCEPTED

input
100000 100000
21701 85599
61542 21474
38081 29362
46316 64038
...

correct output
60593

user output
60593

Test 13

Group: 3

Verdict: ACCEPTED

input
100000 50000
86469 4833
16351 35505
59315 33011
95464 16985
...

correct output
35933

user output
35933

Test 14

Group: 3

Verdict: ACCEPTED

input
100000 40000
5392 23534
63204 45619
74330 25925
59678 88427
...

correct output
30074

user output
30074

Test 15

Group: 3

Verdict: ACCEPTED

input
100000 20000
80156 16531
71753 77661
7028 33389
17168 646
...

correct output
16882

user output
16882