Submission #63207

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
63207	2018-08-01T05:56:43 Z	김세빈(#1833)	Alternating Current (BOI18_alternating)	C++11	33 / 100	3000 ms	18152 KB

alternating

#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[P[i].first].push_back(i);
				x = i;
			}
		}
		else Y[P[i].first].push_back(i);
	}
	
	ans[x] = 1;
	s = P[x].first, e = P[x].second;
	
	for(i=s; ; ){
		for(int &t: X[i]){
			if(P[t].first < P[t].second){
				if(i <= e && e < P[t].second) e = P[t].second;
			}
			else{
				if(i <= e) e = P[t].second;
				else if(e < P[t].second) e = P[t].second;
			}
		}
		for(int &t: Y[i]) y = t;
		
		if(i == e){
			ans[y] = 1;
			e = P[y].second;
		}
		
		i ++; if(i > n) i -= n;
		if(i == s) break;
	}
	
	for(i=1; i<=m; i++){
		if(ans[i] == 0){
			if(P[i].first < P[i].second){
				for(int j=P[i].first; j<P[i].second; j++) fff[j] = 1;
			}
			else{
				for(int j=P[i].first; j<=n; j++) fff[j] = 1;
				for(int j=1; j<P[i].second; j++) fff[j] = 1;
			}
		}
	}
	
	for(i=1; i<=n; i++){
		if(!fff[i]) die();
		fff[i] = 0;
	}
	
	for(i=1; i<=m; i++){
		if(ans[i] == 1){
			if(P[i].first < P[i].second){
				for(int j=P[i].first; j<P[i].second; j++) fff[j] = 1;
			}
			else{
				for(int j=P[i].first; j<=n; j++) fff[j] = 1;
				for(int j=1; j<P[i].second; j++) fff[j] = 1;
			}
		}
	}
	
	for(i=1; i<=n; i++){
		if(!fff[i]) die();
		fff[i] = 0;
	}
	
	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);
   ~~~~~^~~~~~~~~~~~~~~~
alternating.cpp:95:6: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
    e = P[y].second;
    ~~^~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	9720 KB	Output is correct
2	Correct	10 ms	9828 KB	Output is correct
3	Correct	10 ms	9880 KB	Output is correct
4	Correct	13 ms	9900 KB	Output is correct
5	Correct	13 ms	9940 KB	Output is correct
6	Correct	10 ms	9988 KB	Output is correct
7	Correct	10 ms	9988 KB	Output is correct
8	Correct	11 ms	10064 KB	Output is correct
9	Correct	11 ms	10064 KB	Output is correct
10	Correct	11 ms	10064 KB	Output is correct
11	Correct	12 ms	10092 KB	Output is correct
12	Correct	10 ms	10092 KB	Output is correct
13	Correct	10 ms	10092 KB	Output is correct
14	Correct	10 ms	10092 KB	Output is correct
15	Correct	12 ms	10092 KB	Output is correct
16	Correct	13 ms	10224 KB	Output is correct
17	Correct	10 ms	10224 KB	Output is correct
18	Correct	10 ms	10224 KB	Output is correct
19	Correct	11 ms	10224 KB	Output is correct
20	Correct	12 ms	10224 KB	Output is correct
21	Correct	11 ms	10224 KB	Output is correct
22	Correct	12 ms	10224 KB	Output is correct
23	Correct	13 ms	10236 KB	Output is correct
24	Correct	11 ms	10236 KB	Output is correct
25	Correct	12 ms	10236 KB	Output is correct
26	Correct	13 ms	10236 KB	Output is correct
27	Correct	10 ms	10236 KB	Output is correct
28	Correct	12 ms	10236 KB	Output is correct
29	Correct	12 ms	10236 KB	Output is correct
30	Correct	11 ms	10236 KB	Output is correct
31	Correct	11 ms	10236 KB	Output is correct
32	Correct	11 ms	10236 KB	Output is correct
33	Correct	10 ms	10236 KB	Output is correct
34	Correct	12 ms	10236 KB	Output is correct
35	Correct	12 ms	10236 KB	Output is correct
36	Correct	12 ms	10236 KB	Output is correct
37	Correct	11 ms	10236 KB	Output is correct
38	Correct	13 ms	10236 KB	Output is correct
39	Correct	12 ms	10236 KB	Output is correct
40	Correct	13 ms	10236 KB	Output is correct

Subtask #2
20.0 / 20.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	9720 KB	Output is correct
2	Correct	10 ms	9828 KB	Output is correct
3	Correct	10 ms	9880 KB	Output is correct
4	Correct	13 ms	9900 KB	Output is correct
5	Correct	13 ms	9940 KB	Output is correct
6	Correct	10 ms	9988 KB	Output is correct
7	Correct	10 ms	9988 KB	Output is correct
8	Correct	11 ms	10064 KB	Output is correct
9	Correct	11 ms	10064 KB	Output is correct
10	Correct	11 ms	10064 KB	Output is correct
11	Correct	12 ms	10092 KB	Output is correct
12	Correct	10 ms	10092 KB	Output is correct
13	Correct	10 ms	10092 KB	Output is correct
14	Correct	10 ms	10092 KB	Output is correct
15	Correct	12 ms	10092 KB	Output is correct
16	Correct	13 ms	10224 KB	Output is correct
17	Correct	10 ms	10224 KB	Output is correct
18	Correct	10 ms	10224 KB	Output is correct
19	Correct	11 ms	10224 KB	Output is correct
20	Correct	12 ms	10224 KB	Output is correct
21	Correct	11 ms	10224 KB	Output is correct
22	Correct	12 ms	10224 KB	Output is correct
23	Correct	13 ms	10236 KB	Output is correct
24	Correct	11 ms	10236 KB	Output is correct
25	Correct	12 ms	10236 KB	Output is correct
26	Correct	13 ms	10236 KB	Output is correct
27	Correct	10 ms	10236 KB	Output is correct
28	Correct	12 ms	10236 KB	Output is correct
29	Correct	12 ms	10236 KB	Output is correct
30	Correct	11 ms	10236 KB	Output is correct
31	Correct	11 ms	10236 KB	Output is correct
32	Correct	11 ms	10236 KB	Output is correct
33	Correct	10 ms	10236 KB	Output is correct
34	Correct	12 ms	10236 KB	Output is correct
35	Correct	12 ms	10236 KB	Output is correct
36	Correct	12 ms	10236 KB	Output is correct
37	Correct	11 ms	10236 KB	Output is correct
38	Correct	13 ms	10236 KB	Output is correct
39	Correct	12 ms	10236 KB	Output is correct
40	Correct	13 ms	10236 KB	Output is correct
41	Correct	12 ms	10236 KB	Output is correct
42	Correct	12 ms	10236 KB	Output is correct
43	Correct	11 ms	10236 KB	Output is correct
44	Correct	14 ms	10236 KB	Output is correct
45	Correct	15 ms	10236 KB	Output is correct
46	Correct	14 ms	10236 KB	Output is correct
47	Correct	12 ms	10236 KB	Output is correct
48	Correct	10 ms	10236 KB	Output is correct
49	Correct	10 ms	10236 KB	Output is correct
50	Correct	10 ms	10236 KB	Output is correct
51	Correct	12 ms	10236 KB	Output is correct
52	Correct	11 ms	10236 KB	Output is correct
53	Correct	12 ms	10236 KB	Output is correct
54	Correct	11 ms	10236 KB	Output is correct
55	Correct	11 ms	10236 KB	Output is correct
56	Correct	11 ms	10236 KB	Output is correct
57	Correct	13 ms	10236 KB	Output is correct
58	Correct	12 ms	10236 KB	Output is correct
59	Correct	13 ms	10236 KB	Output is correct
60	Correct	13 ms	10236 KB	Output is correct
61	Correct	12 ms	10236 KB	Output is correct
62	Correct	10 ms	10236 KB	Output is correct
63	Correct	10 ms	10236 KB	Output is correct
64	Correct	12 ms	10236 KB	Output is correct
65	Correct	12 ms	10236 KB	Output is correct
66	Correct	12 ms	10236 KB	Output is correct
67	Correct	12 ms	10236 KB	Output is correct
68	Correct	10 ms	10236 KB	Output is correct
69	Correct	13 ms	10236 KB	Output is correct

Subtask #3
0 / 22.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	9720 KB	Output is correct
2	Correct	10 ms	9828 KB	Output is correct
3	Correct	10 ms	9880 KB	Output is correct
4	Correct	13 ms	9900 KB	Output is correct
5	Correct	13 ms	9940 KB	Output is correct
6	Correct	10 ms	9988 KB	Output is correct
7	Correct	10 ms	9988 KB	Output is correct
8	Correct	11 ms	10064 KB	Output is correct
9	Correct	11 ms	10064 KB	Output is correct
10	Correct	11 ms	10064 KB	Output is correct
11	Correct	12 ms	10092 KB	Output is correct
12	Correct	10 ms	10092 KB	Output is correct
13	Correct	10 ms	10092 KB	Output is correct
14	Correct	10 ms	10092 KB	Output is correct
15	Correct	12 ms	10092 KB	Output is correct
16	Correct	13 ms	10224 KB	Output is correct
17	Correct	10 ms	10224 KB	Output is correct
18	Correct	10 ms	10224 KB	Output is correct
19	Correct	11 ms	10224 KB	Output is correct
20	Correct	12 ms	10224 KB	Output is correct
21	Correct	11 ms	10224 KB	Output is correct
22	Correct	12 ms	10224 KB	Output is correct
23	Correct	13 ms	10236 KB	Output is correct
24	Correct	11 ms	10236 KB	Output is correct
25	Correct	12 ms	10236 KB	Output is correct
26	Correct	13 ms	10236 KB	Output is correct
27	Correct	10 ms	10236 KB	Output is correct
28	Correct	12 ms	10236 KB	Output is correct
29	Correct	12 ms	10236 KB	Output is correct
30	Correct	11 ms	10236 KB	Output is correct
31	Correct	11 ms	10236 KB	Output is correct
32	Correct	11 ms	10236 KB	Output is correct
33	Correct	10 ms	10236 KB	Output is correct
34	Correct	12 ms	10236 KB	Output is correct
35	Correct	12 ms	10236 KB	Output is correct
36	Correct	12 ms	10236 KB	Output is correct
37	Correct	11 ms	10236 KB	Output is correct
38	Correct	13 ms	10236 KB	Output is correct
39	Correct	12 ms	10236 KB	Output is correct
40	Correct	13 ms	10236 KB	Output is correct
41	Correct	12 ms	10236 KB	Output is correct
42	Correct	12 ms	10236 KB	Output is correct
43	Correct	11 ms	10236 KB	Output is correct
44	Correct	14 ms	10236 KB	Output is correct
45	Correct	15 ms	10236 KB	Output is correct
46	Correct	14 ms	10236 KB	Output is correct
47	Correct	12 ms	10236 KB	Output is correct
48	Correct	10 ms	10236 KB	Output is correct
49	Correct	10 ms	10236 KB	Output is correct
50	Correct	10 ms	10236 KB	Output is correct
51	Correct	12 ms	10236 KB	Output is correct
52	Correct	11 ms	10236 KB	Output is correct
53	Correct	12 ms	10236 KB	Output is correct
54	Correct	11 ms	10236 KB	Output is correct
55	Correct	11 ms	10236 KB	Output is correct
56	Correct	11 ms	10236 KB	Output is correct
57	Correct	13 ms	10236 KB	Output is correct
58	Correct	12 ms	10236 KB	Output is correct
59	Correct	13 ms	10236 KB	Output is correct
60	Correct	13 ms	10236 KB	Output is correct
61	Correct	12 ms	10236 KB	Output is correct
62	Correct	10 ms	10236 KB	Output is correct
63	Correct	10 ms	10236 KB	Output is correct
64	Correct	12 ms	10236 KB	Output is correct
65	Correct	12 ms	10236 KB	Output is correct
66	Correct	12 ms	10236 KB	Output is correct
67	Correct	12 ms	10236 KB	Output is correct
68	Correct	10 ms	10236 KB	Output is correct
69	Correct	13 ms	10236 KB	Output is correct
70	Correct	12 ms	10236 KB	Output is correct
71	Correct	13 ms	10236 KB	Output is correct
72	Correct	12 ms	10236 KB	Output is correct
73	Correct	11 ms	10236 KB	Output is correct
74	Correct	10 ms	10236 KB	Output is correct
75	Correct	11 ms	10236 KB	Output is correct
76	Correct	15 ms	10236 KB	Output is correct
77	Correct	13 ms	10236 KB	Output is correct
78	Correct	10 ms	10236 KB	Output is correct
79	Correct	14 ms	10236 KB	Output is correct
80	Correct	12 ms	10236 KB	Output is correct
81	Incorrect	13 ms	10236 KB	'impossible' claimed, but there is a solution
82	Halted	0 ms	0 KB	-

Subtask #4
0 / 19.0

#	Verdict	Execution time	Memory	Grader output
1	Execution timed out	3037 ms	18152 KB	Time limit exceeded
2	Halted	0 ms	0 KB	-

Subtask #5
0 / 26.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	9720 KB	Output is correct
2	Correct	10 ms	9828 KB	Output is correct
3	Correct	10 ms	9880 KB	Output is correct
4	Correct	13 ms	9900 KB	Output is correct
5	Correct	13 ms	9940 KB	Output is correct
6	Correct	10 ms	9988 KB	Output is correct
7	Correct	10 ms	9988 KB	Output is correct
8	Correct	11 ms	10064 KB	Output is correct
9	Correct	11 ms	10064 KB	Output is correct
10	Correct	11 ms	10064 KB	Output is correct
11	Correct	12 ms	10092 KB	Output is correct
12	Correct	10 ms	10092 KB	Output is correct
13	Correct	10 ms	10092 KB	Output is correct
14	Correct	10 ms	10092 KB	Output is correct
15	Correct	12 ms	10092 KB	Output is correct
16	Correct	13 ms	10224 KB	Output is correct
17	Correct	10 ms	10224 KB	Output is correct
18	Correct	10 ms	10224 KB	Output is correct
19	Correct	11 ms	10224 KB	Output is correct
20	Correct	12 ms	10224 KB	Output is correct
21	Correct	11 ms	10224 KB	Output is correct
22	Correct	12 ms	10224 KB	Output is correct
23	Correct	13 ms	10236 KB	Output is correct
24	Correct	11 ms	10236 KB	Output is correct
25	Correct	12 ms	10236 KB	Output is correct
26	Correct	13 ms	10236 KB	Output is correct
27	Correct	10 ms	10236 KB	Output is correct
28	Correct	12 ms	10236 KB	Output is correct
29	Correct	12 ms	10236 KB	Output is correct
30	Correct	11 ms	10236 KB	Output is correct
31	Correct	11 ms	10236 KB	Output is correct
32	Correct	11 ms	10236 KB	Output is correct
33	Correct	10 ms	10236 KB	Output is correct
34	Correct	12 ms	10236 KB	Output is correct
35	Correct	12 ms	10236 KB	Output is correct
36	Correct	12 ms	10236 KB	Output is correct
37	Correct	11 ms	10236 KB	Output is correct
38	Correct	13 ms	10236 KB	Output is correct
39	Correct	12 ms	10236 KB	Output is correct
40	Correct	13 ms	10236 KB	Output is correct
41	Correct	12 ms	10236 KB	Output is correct
42	Correct	12 ms	10236 KB	Output is correct
43	Correct	11 ms	10236 KB	Output is correct
44	Correct	14 ms	10236 KB	Output is correct
45	Correct	15 ms	10236 KB	Output is correct
46	Correct	14 ms	10236 KB	Output is correct
47	Correct	12 ms	10236 KB	Output is correct
48	Correct	10 ms	10236 KB	Output is correct
49	Correct	10 ms	10236 KB	Output is correct
50	Correct	10 ms	10236 KB	Output is correct
51	Correct	12 ms	10236 KB	Output is correct
52	Correct	11 ms	10236 KB	Output is correct
53	Correct	12 ms	10236 KB	Output is correct
54	Correct	11 ms	10236 KB	Output is correct
55	Correct	11 ms	10236 KB	Output is correct
56	Correct	11 ms	10236 KB	Output is correct
57	Correct	13 ms	10236 KB	Output is correct
58	Correct	12 ms	10236 KB	Output is correct
59	Correct	13 ms	10236 KB	Output is correct
60	Correct	13 ms	10236 KB	Output is correct
61	Correct	12 ms	10236 KB	Output is correct
62	Correct	10 ms	10236 KB	Output is correct
63	Correct	10 ms	10236 KB	Output is correct
64	Correct	12 ms	10236 KB	Output is correct
65	Correct	12 ms	10236 KB	Output is correct
66	Correct	12 ms	10236 KB	Output is correct
67	Correct	12 ms	10236 KB	Output is correct
68	Correct	10 ms	10236 KB	Output is correct
69	Correct	13 ms	10236 KB	Output is correct
70	Correct	12 ms	10236 KB	Output is correct
71	Correct	13 ms	10236 KB	Output is correct
72	Correct	12 ms	10236 KB	Output is correct
73	Correct	11 ms	10236 KB	Output is correct
74	Correct	10 ms	10236 KB	Output is correct
75	Correct	11 ms	10236 KB	Output is correct
76	Correct	15 ms	10236 KB	Output is correct
77	Correct	13 ms	10236 KB	Output is correct
78	Correct	10 ms	10236 KB	Output is correct
79	Correct	14 ms	10236 KB	Output is correct
80	Correct	12 ms	10236 KB	Output is correct
81	Incorrect	13 ms	10236 KB	'impossible' claimed, but there is a solution
82	Halted	0 ms	0 KB	-

Submission #63207

Compilation message

Subtask #1 13.0 / 13.0

Subtask #2 20.0 / 20.0

Subtask #3 0 / 22.0

Subtask #4 0 / 19.0

Subtask #5 0 / 26.0

Subtask #1
13.0 / 13.0

Subtask #2
20.0 / 20.0

Subtask #3
0 / 22.0

Subtask #4
0 / 19.0

Subtask #5
0 / 26.0