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Submission #63204

# Submission time Handle Problem Language Result Execution time Memory
63204 2018-08-01T05:49:05 Z 김세빈(#1833) Alternating Current (BOI18_alternating) C++11
0 / 100
 192 ms 18572 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 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);
	}
	
	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++) printf("%d", ans[i]);
	printf("\n");
	
	return 0;
}

Compilation message

alternating.cpp: In function 'int main()':
alternating.cpp:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~
alternating.cpp:32:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~
alternating.cpp:93:6: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
    e = P[y].second;
    ~~^~~~~~~~~~~~~

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 10 ms 9848 KB Output is correct
3 Correct 11 ms 10032 KB Output is correct
4 Correct 12 ms 10032 KB Output is correct
5 Correct 12 ms 10032 KB Output is correct
6 Correct 12 ms 10084 KB Output is correct
7 Correct 13 ms 10084 KB Output is correct
8 Correct 11 ms 10084 KB Output is correct
9 Correct 10 ms 10104 KB Output is correct
10 Correct 18 ms 10104 KB Output is correct
11 Correct 13 ms 10104 KB Output is correct
12 Correct 11 ms 10104 KB Output is correct
13 Correct 12 ms 10104 KB Output is correct
14 Correct 10 ms 10108 KB Output is correct
15 Correct 13 ms 10112 KB Output is correct
16 Correct 12 ms 10236 KB Output is correct
17 Correct 16 ms 10236 KB Output is correct
18 Correct 10 ms 10236 KB Output is correct
19 Correct 11 ms 10236 KB Output is correct
20 Correct 11 ms 10236 KB Output is correct
21 Correct 12 ms 10236 KB Output is correct
22 Correct 11 ms 10236 KB Output is correct
23 Correct 14 ms 10236 KB Output is correct
24 Correct 13 ms 10236 KB Output is correct
25 Correct 12 ms 10236 KB Output is correct
26 Correct 11 ms 10236 KB Output is correct
27 Incorrect 12 ms 10236 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 10 ms 9848 KB Output is correct
3 Correct 11 ms 10032 KB Output is correct
4 Correct 12 ms 10032 KB Output is correct
5 Correct 12 ms 10032 KB Output is correct
6 Correct 12 ms 10084 KB Output is correct
7 Correct 13 ms 10084 KB Output is correct
8 Correct 11 ms 10084 KB Output is correct
9 Correct 10 ms 10104 KB Output is correct
10 Correct 18 ms 10104 KB Output is correct
11 Correct 13 ms 10104 KB Output is correct
12 Correct 11 ms 10104 KB Output is correct
13 Correct 12 ms 10104 KB Output is correct
14 Correct 10 ms 10108 KB Output is correct
15 Correct 13 ms 10112 KB Output is correct
16 Correct 12 ms 10236 KB Output is correct
17 Correct 16 ms 10236 KB Output is correct
18 Correct 10 ms 10236 KB Output is correct
19 Correct 11 ms 10236 KB Output is correct
20 Correct 11 ms 10236 KB Output is correct
21 Correct 12 ms 10236 KB Output is correct
22 Correct 11 ms 10236 KB Output is correct
23 Correct 14 ms 10236 KB Output is correct
24 Correct 13 ms 10236 KB Output is correct
25 Correct 12 ms 10236 KB Output is correct
26 Correct 11 ms 10236 KB Output is correct
27 Incorrect 12 ms 10236 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 10 ms 9848 KB Output is correct
3 Correct 11 ms 10032 KB Output is correct
4 Correct 12 ms 10032 KB Output is correct
5 Correct 12 ms 10032 KB Output is correct
6 Correct 12 ms 10084 KB Output is correct
7 Correct 13 ms 10084 KB Output is correct
8 Correct 11 ms 10084 KB Output is correct
9 Correct 10 ms 10104 KB Output is correct
10 Correct 18 ms 10104 KB Output is correct
11 Correct 13 ms 10104 KB Output is correct
12 Correct 11 ms 10104 KB Output is correct
13 Correct 12 ms 10104 KB Output is correct
14 Correct 10 ms 10108 KB Output is correct
15 Correct 13 ms 10112 KB Output is correct
16 Correct 12 ms 10236 KB Output is correct
17 Correct 16 ms 10236 KB Output is correct
18 Correct 10 ms 10236 KB Output is correct
19 Correct 11 ms 10236 KB Output is correct
20 Correct 11 ms 10236 KB Output is correct
21 Correct 12 ms 10236 KB Output is correct
22 Correct 11 ms 10236 KB Output is correct
23 Correct 14 ms 10236 KB Output is correct
24 Correct 13 ms 10236 KB Output is correct
25 Correct 12 ms 10236 KB Output is correct
26 Correct 11 ms 10236 KB Output is correct
27 Incorrect 12 ms 10236 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 140 ms 17832 KB Output is correct
2 Correct 20 ms 17832 KB Output is correct
3 Correct 43 ms 17832 KB Output is correct
4 Correct 64 ms 17832 KB Output is correct
5 Correct 192 ms 18572 KB Output is correct
6 Correct 111 ms 18572 KB Output is correct
7 Correct 184 ms 18572 KB Output is correct
8 Incorrect 19 ms 18572 KB no wires in direction 1 between segments 23246 and 23255
9 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 9848 KB Output is correct
2 Correct 10 ms 9848 KB Output is correct
3 Correct 11 ms 10032 KB Output is correct
4 Correct 12 ms 10032 KB Output is correct
5 Correct 12 ms 10032 KB Output is correct
6 Correct 12 ms 10084 KB Output is correct
7 Correct 13 ms 10084 KB Output is correct
8 Correct 11 ms 10084 KB Output is correct
9 Correct 10 ms 10104 KB Output is correct
10 Correct 18 ms 10104 KB Output is correct
11 Correct 13 ms 10104 KB Output is correct
12 Correct 11 ms 10104 KB Output is correct
13 Correct 12 ms 10104 KB Output is correct
14 Correct 10 ms 10108 KB Output is correct
15 Correct 13 ms 10112 KB Output is correct
16 Correct 12 ms 10236 KB Output is correct
17 Correct 16 ms 10236 KB Output is correct
18 Correct 10 ms 10236 KB Output is correct
19 Correct 11 ms 10236 KB Output is correct
20 Correct 11 ms 10236 KB Output is correct
21 Correct 12 ms 10236 KB Output is correct
22 Correct 11 ms 10236 KB Output is correct
23 Correct 14 ms 10236 KB Output is correct
24 Correct 13 ms 10236 KB Output is correct
25 Correct 12 ms 10236 KB Output is correct
26 Correct 11 ms 10236 KB Output is correct
27 Incorrect 12 ms 10236 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -