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Submission #63233

# Submission time Handle Problem Language Result Execution time Memory
63233 2018-08-01T06:44:09 Z 김세빈(#1833) Alternating Current (BOI18_alternating) C++11
13 / 100
 178 ms 18444 KB 
#include <bits/stdc++.h>

using namespace std;

typedef pair <int, int> pii;

vector <int> L[101010], V[101010];
vector <int> X[101010], Y[101010];
set <int> S;
pii P[101010];
int chk[101010], ans[101010];
int fff[101010];
int n, m;

void die() { printf("impossible\n"); exit(0); }

void dfs(int p, int c)
{
	chk[p] = 2; ans[p] = c;
	for(int &t: V[p]){
		if(chk[t] == 1) dfs(t, !c);
		else if(ans[t] == ans[p]) die();
	}
}

int main()
{
	int i, s, e, x, y, a, b;
	
	scanf("%d%d", &n, &m);
	
	for(i=1; i<=m; i++){
		scanf("%d%d", &a, &b);
		b ++; if(b > n) b -= n;
		P[i] = pii(a, b);
		if(a < b){
			L[a].push_back(i);
			L[b].push_back(-i);
		}
		else{
			L[1].push_back(i);
			L[b].push_back(-i);
			L[a].push_back(i);
		}
	}
	
	for(i=1; i<=n; i++){
		for(int &t: L[i]){
			if(t > 0) S.insert(t);
			else S.erase(-t);
		}
		
		if(S.size() == 2){
			a = *S.begin(); b = *next(S.begin());
			V[a].push_back(b);
			V[b].push_back(a);
			chk[a] = 1; chk[b] = 1;
		}
		else if(S.size() == 1) die();
	}
	
	for(i=1; i<=m; i++){
		if(chk[i] == 1) dfs(i, 0);
	}
	
	x = 1;
	
	for(i=1; i<=m; i++){
		if(chk[i]){
			if(ans[i] == 1) x = i;
		}
	}
	
	ans[x] = 1;
	s = P[x].first;
	
	for(i=1; i<=m; i++){
		P[i].first = (P[i].first - s + n) % n + 1;
		P[i].second = (P[i].second - s + n) % n + 1;
		if(P[i].first >= P[i].second) P[i].second += n;
		
		if(chk[i] && ans[i] == 1) X[P[i].first].push_back(i);
		else if(!chk[i]) Y[P[i].first].push_back(i);
	}
	
	e = P[x].second; y = -1;
	
	for(i=1; i<=n; i++){
		for(int &t: X[i]) e = max(e, P[t].second);
		for(int &t: Y[i]) y = t;
		
		if(i == e){
			if(y == -1) die();
			ans[y] = 1;
			e = P[y].second;
			y = -1;
		}
	}
	
	for(i=1; i<=m; i++) printf("%d", ans[i]);
	printf("\n");
	
	return 0;
}

Compilation message

alternating.cpp: In function 'int main()':
alternating.cpp:30:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~
alternating.cpp:33:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9848 KB Output is correct
2 Correct 12 ms 9848 KB Output is correct
3 Correct 10 ms 9884 KB Output is correct
4 Correct 12 ms 9992 KB Output is correct
5 Correct 10 ms 9992 KB Output is correct
6 Correct 10 ms 9992 KB Output is correct
7 Correct 12 ms 9992 KB Output is correct
8 Correct 11 ms 10096 KB Output is correct
9 Correct 11 ms 10096 KB Output is correct
10 Correct 11 ms 10096 KB Output is correct
11 Correct 10 ms 10096 KB Output is correct
12 Correct 11 ms 10096 KB Output is correct
13 Correct 12 ms 10096 KB Output is correct
14 Correct 14 ms 10096 KB Output is correct
15 Correct 12 ms 10096 KB Output is correct
16 Correct 13 ms 10096 KB Output is correct
17 Correct 12 ms 10096 KB Output is correct
18 Correct 12 ms 10096 KB Output is correct
19 Correct 11 ms 10096 KB Output is correct
20 Correct 12 ms 10096 KB Output is correct
21 Correct 12 ms 10096 KB Output is correct
22 Correct 10 ms 10096 KB Output is correct
23 Correct 12 ms 10096 KB Output is correct
24 Correct 11 ms 10096 KB Output is correct
25 Correct 12 ms 10096 KB Output is correct
26 Correct 11 ms 10096 KB Output is correct
27 Correct 11 ms 10096 KB Output is correct
28 Correct 11 ms 10096 KB Output is correct
29 Correct 12 ms 10096 KB Output is correct
30 Correct 10 ms 10096 KB Output is correct
31 Correct 14 ms 10096 KB Output is correct
32 Correct 13 ms 10096 KB Output is correct
33 Correct 12 ms 10096 KB Output is correct
34 Correct 10 ms 10096 KB Output is correct
35 Correct 12 ms 10096 KB Output is correct
36 Correct 11 ms 10096 KB Output is correct
37 Correct 12 ms 10096 KB Output is correct
38 Correct 13 ms 10096 KB Output is correct
39 Correct 9 ms 10096 KB Output is correct
40 Correct 13 ms 10096 KB Output is correct

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9848 KB Output is correct
2 Correct 12 ms 9848 KB Output is correct
3 Correct 10 ms 9884 KB Output is correct
4 Correct 12 ms 9992 KB Output is correct
5 Correct 10 ms 9992 KB Output is correct
6 Correct 10 ms 9992 KB Output is correct
7 Correct 12 ms 9992 KB Output is correct
8 Correct 11 ms 10096 KB Output is correct
9 Correct 11 ms 10096 KB Output is correct
10 Correct 11 ms 10096 KB Output is correct
11 Correct 10 ms 10096 KB Output is correct
12 Correct 11 ms 10096 KB Output is correct
13 Correct 12 ms 10096 KB Output is correct
14 Correct 14 ms 10096 KB Output is correct
15 Correct 12 ms 10096 KB Output is correct
16 Correct 13 ms 10096 KB Output is correct
17 Correct 12 ms 10096 KB Output is correct
18 Correct 12 ms 10096 KB Output is correct
19 Correct 11 ms 10096 KB Output is correct
20 Correct 12 ms 10096 KB Output is correct
21 Correct 12 ms 10096 KB Output is correct
22 Correct 10 ms 10096 KB Output is correct
23 Correct 12 ms 10096 KB Output is correct
24 Correct 11 ms 10096 KB Output is correct
25 Correct 12 ms 10096 KB Output is correct
26 Correct 11 ms 10096 KB Output is correct
27 Correct 11 ms 10096 KB Output is correct
28 Correct 11 ms 10096 KB Output is correct
29 Correct 12 ms 10096 KB Output is correct
30 Correct 10 ms 10096 KB Output is correct
31 Correct 14 ms 10096 KB Output is correct
32 Correct 13 ms 10096 KB Output is correct
33 Correct 12 ms 10096 KB Output is correct
34 Correct 10 ms 10096 KB Output is correct
35 Correct 12 ms 10096 KB Output is correct
36 Correct 11 ms 10096 KB Output is correct
37 Correct 12 ms 10096 KB Output is correct
38 Correct 13 ms 10096 KB Output is correct
39 Correct 9 ms 10096 KB Output is correct
40 Correct 13 ms 10096 KB Output is correct
41 Correct 14 ms 10096 KB Output is correct
42 Correct 13 ms 10108 KB Output is correct
43 Correct 12 ms 10108 KB Output is correct
44 Correct 11 ms 10108 KB Output is correct
45 Correct 11 ms 10108 KB Output is correct
46 Correct 11 ms 10108 KB Output is correct
47 Correct 11 ms 10108 KB Output is correct
48 Correct 13 ms 10108 KB Output is correct
49 Correct 13 ms 10108 KB Output is correct
50 Correct 12 ms 10108 KB Output is correct
51 Correct 11 ms 10108 KB Output is correct
52 Correct 13 ms 10220 KB Output is correct
53 Correct 13 ms 10220 KB Output is correct
54 Correct 12 ms 10220 KB Output is correct
55 Correct 12 ms 10220 KB Output is correct
56 Correct 13 ms 10220 KB Output is correct
57 Correct 14 ms 10220 KB Output is correct
58 Correct 14 ms 10220 KB Output is correct
59 Correct 12 ms 10220 KB Output is correct
60 Correct 14 ms 10220 KB Output is correct
61 Correct 12 ms 10220 KB Output is correct
62 Incorrect 12 ms 10220 KB no wires in direction 0 between segments 59 and 59
63 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9848 KB Output is correct
2 Correct 12 ms 9848 KB Output is correct
3 Correct 10 ms 9884 KB Output is correct
4 Correct 12 ms 9992 KB Output is correct
5 Correct 10 ms 9992 KB Output is correct
6 Correct 10 ms 9992 KB Output is correct
7 Correct 12 ms 9992 KB Output is correct
8 Correct 11 ms 10096 KB Output is correct
9 Correct 11 ms 10096 KB Output is correct
10 Correct 11 ms 10096 KB Output is correct
11 Correct 10 ms 10096 KB Output is correct
12 Correct 11 ms 10096 KB Output is correct
13 Correct 12 ms 10096 KB Output is correct
14 Correct 14 ms 10096 KB Output is correct
15 Correct 12 ms 10096 KB Output is correct
16 Correct 13 ms 10096 KB Output is correct
17 Correct 12 ms 10096 KB Output is correct
18 Correct 12 ms 10096 KB Output is correct
19 Correct 11 ms 10096 KB Output is correct
20 Correct 12 ms 10096 KB Output is correct
21 Correct 12 ms 10096 KB Output is correct
22 Correct 10 ms 10096 KB Output is correct
23 Correct 12 ms 10096 KB Output is correct
24 Correct 11 ms 10096 KB Output is correct
25 Correct 12 ms 10096 KB Output is correct
26 Correct 11 ms 10096 KB Output is correct
27 Correct 11 ms 10096 KB Output is correct
28 Correct 11 ms 10096 KB Output is correct
29 Correct 12 ms 10096 KB Output is correct
30 Correct 10 ms 10096 KB Output is correct
31 Correct 14 ms 10096 KB Output is correct
32 Correct 13 ms 10096 KB Output is correct
33 Correct 12 ms 10096 KB Output is correct
34 Correct 10 ms 10096 KB Output is correct
35 Correct 12 ms 10096 KB Output is correct
36 Correct 11 ms 10096 KB Output is correct
37 Correct 12 ms 10096 KB Output is correct
38 Correct 13 ms 10096 KB Output is correct
39 Correct 9 ms 10096 KB Output is correct
40 Correct 13 ms 10096 KB Output is correct
41 Correct 14 ms 10096 KB Output is correct
42 Correct 13 ms 10108 KB Output is correct
43 Correct 12 ms 10108 KB Output is correct
44 Correct 11 ms 10108 KB Output is correct
45 Correct 11 ms 10108 KB Output is correct
46 Correct 11 ms 10108 KB Output is correct
47 Correct 11 ms 10108 KB Output is correct
48 Correct 13 ms 10108 KB Output is correct
49 Correct 13 ms 10108 KB Output is correct
50 Correct 12 ms 10108 KB Output is correct
51 Correct 11 ms 10108 KB Output is correct
52 Correct 13 ms 10220 KB Output is correct
53 Correct 13 ms 10220 KB Output is correct
54 Correct 12 ms 10220 KB Output is correct
55 Correct 12 ms 10220 KB Output is correct
56 Correct 13 ms 10220 KB Output is correct
57 Correct 14 ms 10220 KB Output is correct
58 Correct 14 ms 10220 KB Output is correct
59 Correct 12 ms 10220 KB Output is correct
60 Correct 14 ms 10220 KB Output is correct
61 Correct 12 ms 10220 KB Output is correct
62 Incorrect 12 ms 10220 KB no wires in direction 0 between segments 59 and 59
63 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 121 ms 17752 KB Output is correct
2 Correct 17 ms 17752 KB Output is correct
3 Correct 38 ms 17752 KB Output is correct
4 Correct 60 ms 17752 KB Output is correct
5 Correct 178 ms 18444 KB Output is correct
6 Correct 127 ms 18444 KB Output is correct
7 Correct 163 ms 18444 KB Output is correct
8 Incorrect 17 ms 18444 KB 'impossible' claimed, but there is a solution
9 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9848 KB Output is correct
2 Correct 12 ms 9848 KB Output is correct
3 Correct 10 ms 9884 KB Output is correct
4 Correct 12 ms 9992 KB Output is correct
5 Correct 10 ms 9992 KB Output is correct
6 Correct 10 ms 9992 KB Output is correct
7 Correct 12 ms 9992 KB Output is correct
8 Correct 11 ms 10096 KB Output is correct
9 Correct 11 ms 10096 KB Output is correct
10 Correct 11 ms 10096 KB Output is correct
11 Correct 10 ms 10096 KB Output is correct
12 Correct 11 ms 10096 KB Output is correct
13 Correct 12 ms 10096 KB Output is correct
14 Correct 14 ms 10096 KB Output is correct
15 Correct 12 ms 10096 KB Output is correct
16 Correct 13 ms 10096 KB Output is correct
17 Correct 12 ms 10096 KB Output is correct
18 Correct 12 ms 10096 KB Output is correct
19 Correct 11 ms 10096 KB Output is correct
20 Correct 12 ms 10096 KB Output is correct
21 Correct 12 ms 10096 KB Output is correct
22 Correct 10 ms 10096 KB Output is correct
23 Correct 12 ms 10096 KB Output is correct
24 Correct 11 ms 10096 KB Output is correct
25 Correct 12 ms 10096 KB Output is correct
26 Correct 11 ms 10096 KB Output is correct
27 Correct 11 ms 10096 KB Output is correct
28 Correct 11 ms 10096 KB Output is correct
29 Correct 12 ms 10096 KB Output is correct
30 Correct 10 ms 10096 KB Output is correct
31 Correct 14 ms 10096 KB Output is correct
32 Correct 13 ms 10096 KB Output is correct
33 Correct 12 ms 10096 KB Output is correct
34 Correct 10 ms 10096 KB Output is correct
35 Correct 12 ms 10096 KB Output is correct
36 Correct 11 ms 10096 KB Output is correct
37 Correct 12 ms 10096 KB Output is correct
38 Correct 13 ms 10096 KB Output is correct
39 Correct 9 ms 10096 KB Output is correct
40 Correct 13 ms 10096 KB Output is correct
41 Correct 14 ms 10096 KB Output is correct
42 Correct 13 ms 10108 KB Output is correct
43 Correct 12 ms 10108 KB Output is correct
44 Correct 11 ms 10108 KB Output is correct
45 Correct 11 ms 10108 KB Output is correct
46 Correct 11 ms 10108 KB Output is correct
47 Correct 11 ms 10108 KB Output is correct
48 Correct 13 ms 10108 KB Output is correct
49 Correct 13 ms 10108 KB Output is correct
50 Correct 12 ms 10108 KB Output is correct
51 Correct 11 ms 10108 KB Output is correct
52 Correct 13 ms 10220 KB Output is correct
53 Correct 13 ms 10220 KB Output is correct
54 Correct 12 ms 10220 KB Output is correct
55 Correct 12 ms 10220 KB Output is correct
56 Correct 13 ms 10220 KB Output is correct
57 Correct 14 ms 10220 KB Output is correct
58 Correct 14 ms 10220 KB Output is correct
59 Correct 12 ms 10220 KB Output is correct
60 Correct 14 ms 10220 KB Output is correct
61 Correct 12 ms 10220 KB Output is correct
62 Incorrect 12 ms 10220 KB no wires in direction 0 between segments 59 and 59
63 Halted 0 ms 0 KB -