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Submission #63220

# Submission time Handle Problem Language Result Execution time Memory
63220 2018-08-01T06:25:16 Z 김세빈(#1833) Alternating Current (BOI18_alternating) C++11
0 / 100
 192 ms 18640 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;
//			else if(P[t].second > P[y].second) y = t;
		}
		
		if(i == e){
			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
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9720 KB Output is correct
2 Correct 10 ms 9828 KB Output is correct
3 Correct 12 ms 9904 KB Output is correct
4 Correct 10 ms 9940 KB Output is correct
5 Correct 11 ms 10016 KB Output is correct
6 Correct 11 ms 10016 KB Output is correct
7 Correct 12 ms 10092 KB Output is correct
8 Correct 12 ms 10092 KB Output is correct
9 Correct 10 ms 10092 KB Output is correct
10 Correct 10 ms 10092 KB Output is correct
11 Correct 11 ms 10092 KB Output is correct
12 Correct 13 ms 10092 KB Output is correct
13 Correct 13 ms 10164 KB Output is correct
14 Correct 12 ms 10164 KB Output is correct
15 Correct 10 ms 10164 KB Output is correct
16 Correct 11 ms 10164 KB Output is correct
17 Correct 13 ms 10164 KB Output is correct
18 Correct 12 ms 10164 KB Output is correct
19 Correct 12 ms 10164 KB Output is correct
20 Correct 12 ms 10164 KB Output is correct
21 Correct 13 ms 10164 KB Output is correct
22 Correct 11 ms 10164 KB Output is correct
23 Correct 12 ms 10164 KB Output is correct
24 Correct 13 ms 10164 KB Output is correct
25 Correct 11 ms 10164 KB Output is correct
26 Correct 12 ms 10164 KB Output is correct
27 Incorrect 14 ms 10208 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 10 ms 9720 KB Output is correct
2 Correct 10 ms 9828 KB Output is correct
3 Correct 12 ms 9904 KB Output is correct
4 Correct 10 ms 9940 KB Output is correct
5 Correct 11 ms 10016 KB Output is correct
6 Correct 11 ms 10016 KB Output is correct
7 Correct 12 ms 10092 KB Output is correct
8 Correct 12 ms 10092 KB Output is correct
9 Correct 10 ms 10092 KB Output is correct
10 Correct 10 ms 10092 KB Output is correct
11 Correct 11 ms 10092 KB Output is correct
12 Correct 13 ms 10092 KB Output is correct
13 Correct 13 ms 10164 KB Output is correct
14 Correct 12 ms 10164 KB Output is correct
15 Correct 10 ms 10164 KB Output is correct
16 Correct 11 ms 10164 KB Output is correct
17 Correct 13 ms 10164 KB Output is correct
18 Correct 12 ms 10164 KB Output is correct
19 Correct 12 ms 10164 KB Output is correct
20 Correct 12 ms 10164 KB Output is correct
21 Correct 13 ms 10164 KB Output is correct
22 Correct 11 ms 10164 KB Output is correct
23 Correct 12 ms 10164 KB Output is correct
24 Correct 13 ms 10164 KB Output is correct
25 Correct 11 ms 10164 KB Output is correct
26 Correct 12 ms 10164 KB Output is correct
27 Incorrect 14 ms 10208 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 10 ms 9720 KB Output is correct
2 Correct 10 ms 9828 KB Output is correct
3 Correct 12 ms 9904 KB Output is correct
4 Correct 10 ms 9940 KB Output is correct
5 Correct 11 ms 10016 KB Output is correct
6 Correct 11 ms 10016 KB Output is correct
7 Correct 12 ms 10092 KB Output is correct
8 Correct 12 ms 10092 KB Output is correct
9 Correct 10 ms 10092 KB Output is correct
10 Correct 10 ms 10092 KB Output is correct
11 Correct 11 ms 10092 KB Output is correct
12 Correct 13 ms 10092 KB Output is correct
13 Correct 13 ms 10164 KB Output is correct
14 Correct 12 ms 10164 KB Output is correct
15 Correct 10 ms 10164 KB Output is correct
16 Correct 11 ms 10164 KB Output is correct
17 Correct 13 ms 10164 KB Output is correct
18 Correct 12 ms 10164 KB Output is correct
19 Correct 12 ms 10164 KB Output is correct
20 Correct 12 ms 10164 KB Output is correct
21 Correct 13 ms 10164 KB Output is correct
22 Correct 11 ms 10164 KB Output is correct
23 Correct 12 ms 10164 KB Output is correct
24 Correct 13 ms 10164 KB Output is correct
25 Correct 11 ms 10164 KB Output is correct
26 Correct 12 ms 10164 KB Output is correct
27 Incorrect 14 ms 10208 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 114 ms 17768 KB Output is correct
2 Correct 14 ms 17768 KB Output is correct
3 Correct 37 ms 17768 KB Output is correct
4 Correct 71 ms 17768 KB Output is correct
5 Correct 161 ms 18640 KB Output is correct
6 Correct 95 ms 18640 KB Output is correct
7 Correct 192 ms 18640 KB Output is correct
8 Incorrect 20 ms 18640 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 10 ms 9720 KB Output is correct
2 Correct 10 ms 9828 KB Output is correct
3 Correct 12 ms 9904 KB Output is correct
4 Correct 10 ms 9940 KB Output is correct
5 Correct 11 ms 10016 KB Output is correct
6 Correct 11 ms 10016 KB Output is correct
7 Correct 12 ms 10092 KB Output is correct
8 Correct 12 ms 10092 KB Output is correct
9 Correct 10 ms 10092 KB Output is correct
10 Correct 10 ms 10092 KB Output is correct
11 Correct 11 ms 10092 KB Output is correct
12 Correct 13 ms 10092 KB Output is correct
13 Correct 13 ms 10164 KB Output is correct
14 Correct 12 ms 10164 KB Output is correct
15 Correct 10 ms 10164 KB Output is correct
16 Correct 11 ms 10164 KB Output is correct
17 Correct 13 ms 10164 KB Output is correct
18 Correct 12 ms 10164 KB Output is correct
19 Correct 12 ms 10164 KB Output is correct
20 Correct 12 ms 10164 KB Output is correct
21 Correct 13 ms 10164 KB Output is correct
22 Correct 11 ms 10164 KB Output is correct
23 Correct 12 ms 10164 KB Output is correct
24 Correct 13 ms 10164 KB Output is correct
25 Correct 11 ms 10164 KB Output is correct
26 Correct 12 ms 10164 KB Output is correct
27 Incorrect 14 ms 10208 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -