# |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
286112 |
2020-08-30T06:51:57 Z |
gratus907 |
Graph (BOI20_graph) |
C++17 |
|
324 ms |
38252 KB |
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define ll long long
#define int ll
#define eps 1e-7
#define all(x) ((x).begin()),((x).end())
#define usecppio ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
using pii = pair<int, int>;
const int INF = 1e12;
const int UNDET = 2;
const int PLUS = 1;
const int MINUS = -1;
const int FIXED = 0;
struct edge
{
int from, to;
double w;
};
struct node
{
int ind, var = UNDET;
double con = 0;
node(int _ind = 0, int _var = UNDET, double _con = 0.0)
{ind = _ind; var = _var; con = _con;}
void print()
{
printf("NODE %lld : ",ind);
if (var == UNDET)
printf("UNDETERMINED NODE\n");
else if (var == FIXED)
printf("%.3lf\n",con);
else
printf("%sx + %.3lf\n",(var==PLUS?"+":"-"),con);
}
};
node ND[101010];
vector <edge> G[101010];
void report_fail()
{
cout << "NO\n";
exit(0);
}
bool visited[101010];
vector <int> topo;
map<int, int> topo_order;
void dfs_run(int rt, bool d = 0)
{
topo.push_back(rt);
visited[rt] = true;
if (ND[rt].var == UNDET)
{
ND[rt].var = PLUS;
ND[rt].con = 0.0;
}
for (edge E : G[rt])
{
int nxt = E.to;
if (visited[nxt]) continue;
if (ND[nxt].var == UNDET)
{
ND[nxt].con = E.w - ND[rt].con;
ND[nxt].var = -ND[rt].var;
dfs_run(nxt, d);
}
else
{
if (ND[nxt].var == ND[rt].var)
continue;
else
{
if (ND[nxt].con + ND[rt].con != E.w)
{
if (d)
{
printf("MISMATCH %lld %lld\n",rt,nxt);
ND[rt].print();
ND[nxt].print();
}
report_fail();
}
else continue;
}
}
}
return;
}
double find_x()
{
double x = INF;
for (int i = topo.size()-1; i >= 0; i--)
{
int cur = topo[i];
for (edge E : G[cur])
{
int nxt = E.to;
if (topo_order[nxt] < i)
{
if (ND[nxt].var == ND[cur].var)
{
double cons = ND[nxt].con + ND[cur].con;
double vars = ND[nxt].var + ND[cur].var;
return (E.w - cons) / vars;
}
else
{
if (ND[nxt].var + ND[cur].var == 0)
{
if (ND[nxt].con + ND[cur].con != E.w)
report_fail();
}
}
}
else continue;
}
}
vector <double> convals;
for (int i = 0; i<topo.size(); i++)
{
convals.push_back((-1)*(ND[topo[i]].var)*ND[topo[i]].con);
}
sort(all(convals));
int sz = convals.size();
return convals[sz/2];
}
void fix_dfs(int rt, double x)
{
visited[rt] = true;
ND[rt].con = ND[rt].var * x + ND[rt].con;
ND[rt].var = FIXED;
for (edge E : G[rt])
{
if (ND[E.to].var != FIXED)
fix_dfs(E.to, x);
}
return;
}
void const_fix(int rt, double xconst)
{
visited[rt] = true;
ND[rt].con = xconst;
ND[rt].var = FIXED;
for (edge E : G[rt])
{
if (ND[E.to].var != FIXED)
const_fix(E.to, E.w-xconst);
}
return;
}
vector <pair<int, double>> cf;
int32_t main()
{
usecppio
int n, m;
cin >> n >> m;
for (int i = 1; i<=n; i++) ND[i].ind = i;
for (int i = 0; i<m; i++)
{
int u, v, w;
cin >> u >> v >> w;
edge e = {u, v, w*1.0};
edge erev = {v, u, w*1.0};
G[u].push_back(e);
G[v].push_back(erev);
if (u == v)
cf.push_back({u, w*0.5});
}
for (auto [u, w] : cf)
{
if (!visited[u])
const_fix(u, w);
}
for (int i = 1; i<=n; i++)
{
topo.clear();
topo_order.clear();
if (!visited[i])
{
dfs_run(i);
for (int j = 0; j<topo.size(); j++)
{
topo_order[topo[j]] = j;
}
double xval = find_x();
fix_dfs(i, xval);
}
}
for (int i = 1; i<=n; i++)
{
for (edge E : G[i])
{
if (ND[E.from].con + ND[E.to].con != E.w)
report_fail();
}
}
cout << "YES\n";
for (int i = 1; i<=n; i++)
cout << fixed << setprecision(10) << ND[i].con << ' ';
}
Compilation message
Graph.cpp: In function 'double find_x()':
Graph.cpp:118:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
118 | for (int i = 0; i<topo.size(); i++)
| ~^~~~~~~~~~~~
Graph.cpp:90:12: warning: unused variable 'x' [-Wunused-variable]
90 | double x = INF;
| ^
Graph.cpp: In function 'int32_t main()':
Graph.cpp:180:30: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
180 | for (int j = 0; j<topo.size(); j++)
| ~^~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5120 KB |
answer = YES |
2 |
Correct |
3 ms |
5120 KB |
answer = YES |
3 |
Correct |
3 ms |
5120 KB |
answer = YES |
4 |
Correct |
3 ms |
5120 KB |
answer = NO |
5 |
Correct |
3 ms |
5120 KB |
answer = YES |
6 |
Correct |
3 ms |
5120 KB |
answer = YES |
7 |
Correct |
3 ms |
5120 KB |
answer = YES |
8 |
Correct |
3 ms |
5120 KB |
answer = YES |
9 |
Correct |
3 ms |
5120 KB |
answer = NO |
10 |
Correct |
3 ms |
5120 KB |
answer = YES |
11 |
Correct |
3 ms |
5120 KB |
answer = YES |
12 |
Correct |
3 ms |
5120 KB |
answer = NO |
13 |
Correct |
3 ms |
5120 KB |
answer = YES |
14 |
Correct |
3 ms |
5120 KB |
answer = YES |
15 |
Correct |
3 ms |
5120 KB |
answer = YES |
16 |
Correct |
3 ms |
5120 KB |
answer = YES |
17 |
Correct |
3 ms |
5120 KB |
answer = YES |
18 |
Correct |
3 ms |
5120 KB |
answer = YES |
19 |
Correct |
3 ms |
5120 KB |
answer = YES |
20 |
Correct |
4 ms |
5120 KB |
answer = YES |
21 |
Correct |
3 ms |
5120 KB |
answer = YES |
22 |
Correct |
3 ms |
5120 KB |
answer = NO |
23 |
Correct |
3 ms |
5120 KB |
answer = NO |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5120 KB |
answer = YES |
2 |
Correct |
3 ms |
5120 KB |
answer = YES |
3 |
Correct |
3 ms |
5120 KB |
answer = YES |
4 |
Correct |
3 ms |
5120 KB |
answer = NO |
5 |
Correct |
3 ms |
5120 KB |
answer = YES |
6 |
Correct |
3 ms |
5120 KB |
answer = YES |
7 |
Correct |
3 ms |
5120 KB |
answer = YES |
8 |
Correct |
3 ms |
5120 KB |
answer = YES |
9 |
Correct |
3 ms |
5120 KB |
answer = NO |
10 |
Correct |
3 ms |
5120 KB |
answer = YES |
11 |
Correct |
3 ms |
5120 KB |
answer = YES |
12 |
Correct |
3 ms |
5120 KB |
answer = NO |
13 |
Correct |
3 ms |
5120 KB |
answer = YES |
14 |
Correct |
3 ms |
5120 KB |
answer = YES |
15 |
Correct |
3 ms |
5120 KB |
answer = YES |
16 |
Correct |
3 ms |
5120 KB |
answer = YES |
17 |
Correct |
3 ms |
5120 KB |
answer = YES |
18 |
Correct |
3 ms |
5120 KB |
answer = YES |
19 |
Correct |
3 ms |
5120 KB |
answer = YES |
20 |
Correct |
4 ms |
5120 KB |
answer = YES |
21 |
Correct |
3 ms |
5120 KB |
answer = YES |
22 |
Correct |
3 ms |
5120 KB |
answer = NO |
23 |
Correct |
3 ms |
5120 KB |
answer = NO |
24 |
Correct |
3 ms |
5120 KB |
answer = YES |
25 |
Correct |
3 ms |
5120 KB |
answer = YES |
26 |
Correct |
4 ms |
5120 KB |
answer = YES |
27 |
Correct |
4 ms |
5120 KB |
answer = YES |
28 |
Correct |
3 ms |
5120 KB |
answer = YES |
29 |
Correct |
4 ms |
5120 KB |
answer = YES |
30 |
Correct |
4 ms |
5120 KB |
answer = NO |
31 |
Correct |
3 ms |
5120 KB |
answer = YES |
32 |
Correct |
4 ms |
5120 KB |
answer = YES |
33 |
Correct |
3 ms |
5120 KB |
answer = YES |
34 |
Correct |
4 ms |
5120 KB |
answer = YES |
35 |
Correct |
3 ms |
5120 KB |
answer = YES |
36 |
Correct |
4 ms |
5120 KB |
answer = YES |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5120 KB |
answer = YES |
2 |
Correct |
3 ms |
5120 KB |
answer = YES |
3 |
Correct |
3 ms |
5120 KB |
answer = YES |
4 |
Correct |
3 ms |
5120 KB |
answer = NO |
5 |
Correct |
3 ms |
5120 KB |
answer = YES |
6 |
Correct |
3 ms |
5120 KB |
answer = YES |
7 |
Correct |
3 ms |
5120 KB |
answer = YES |
8 |
Correct |
3 ms |
5120 KB |
answer = YES |
9 |
Correct |
3 ms |
5120 KB |
answer = NO |
10 |
Correct |
3 ms |
5120 KB |
answer = YES |
11 |
Correct |
3 ms |
5120 KB |
answer = YES |
12 |
Correct |
3 ms |
5120 KB |
answer = NO |
13 |
Correct |
3 ms |
5120 KB |
answer = YES |
14 |
Correct |
3 ms |
5120 KB |
answer = YES |
15 |
Correct |
3 ms |
5120 KB |
answer = YES |
16 |
Correct |
3 ms |
5120 KB |
answer = YES |
17 |
Correct |
3 ms |
5120 KB |
answer = YES |
18 |
Correct |
3 ms |
5120 KB |
answer = YES |
19 |
Correct |
3 ms |
5120 KB |
answer = YES |
20 |
Correct |
4 ms |
5120 KB |
answer = YES |
21 |
Correct |
3 ms |
5120 KB |
answer = YES |
22 |
Correct |
3 ms |
5120 KB |
answer = NO |
23 |
Correct |
3 ms |
5120 KB |
answer = NO |
24 |
Correct |
3 ms |
5120 KB |
answer = YES |
25 |
Correct |
3 ms |
5120 KB |
answer = YES |
26 |
Correct |
4 ms |
5120 KB |
answer = YES |
27 |
Correct |
4 ms |
5120 KB |
answer = YES |
28 |
Correct |
3 ms |
5120 KB |
answer = YES |
29 |
Correct |
4 ms |
5120 KB |
answer = YES |
30 |
Correct |
4 ms |
5120 KB |
answer = NO |
31 |
Correct |
3 ms |
5120 KB |
answer = YES |
32 |
Correct |
4 ms |
5120 KB |
answer = YES |
33 |
Correct |
3 ms |
5120 KB |
answer = YES |
34 |
Correct |
4 ms |
5120 KB |
answer = YES |
35 |
Correct |
3 ms |
5120 KB |
answer = YES |
36 |
Correct |
4 ms |
5120 KB |
answer = YES |
37 |
Correct |
4 ms |
5120 KB |
answer = YES |
38 |
Correct |
4 ms |
5120 KB |
answer = YES |
39 |
Correct |
4 ms |
5248 KB |
answer = YES |
40 |
Correct |
5 ms |
5248 KB |
answer = YES |
41 |
Correct |
4 ms |
5376 KB |
answer = NO |
42 |
Correct |
5 ms |
5248 KB |
answer = YES |
43 |
Correct |
5 ms |
5248 KB |
answer = YES |
44 |
Correct |
5 ms |
5248 KB |
answer = YES |
45 |
Correct |
4 ms |
5248 KB |
answer = YES |
46 |
Correct |
4 ms |
5120 KB |
answer = YES |
47 |
Correct |
4 ms |
5248 KB |
answer = YES |
48 |
Correct |
4 ms |
5248 KB |
answer = YES |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5120 KB |
answer = YES |
2 |
Correct |
3 ms |
5120 KB |
answer = YES |
3 |
Correct |
3 ms |
5120 KB |
answer = YES |
4 |
Correct |
3 ms |
5120 KB |
answer = NO |
5 |
Correct |
3 ms |
5120 KB |
answer = YES |
6 |
Correct |
3 ms |
5120 KB |
answer = YES |
7 |
Correct |
3 ms |
5120 KB |
answer = YES |
8 |
Correct |
3 ms |
5120 KB |
answer = YES |
9 |
Correct |
3 ms |
5120 KB |
answer = NO |
10 |
Correct |
3 ms |
5120 KB |
answer = YES |
11 |
Correct |
3 ms |
5120 KB |
answer = YES |
12 |
Correct |
3 ms |
5120 KB |
answer = NO |
13 |
Correct |
3 ms |
5120 KB |
answer = YES |
14 |
Correct |
3 ms |
5120 KB |
answer = YES |
15 |
Correct |
3 ms |
5120 KB |
answer = YES |
16 |
Correct |
3 ms |
5120 KB |
answer = YES |
17 |
Correct |
3 ms |
5120 KB |
answer = YES |
18 |
Correct |
3 ms |
5120 KB |
answer = YES |
19 |
Correct |
3 ms |
5120 KB |
answer = YES |
20 |
Correct |
4 ms |
5120 KB |
answer = YES |
21 |
Correct |
3 ms |
5120 KB |
answer = YES |
22 |
Correct |
3 ms |
5120 KB |
answer = NO |
23 |
Correct |
3 ms |
5120 KB |
answer = NO |
24 |
Correct |
3 ms |
5120 KB |
answer = YES |
25 |
Correct |
3 ms |
5120 KB |
answer = YES |
26 |
Correct |
4 ms |
5120 KB |
answer = YES |
27 |
Correct |
4 ms |
5120 KB |
answer = YES |
28 |
Correct |
3 ms |
5120 KB |
answer = YES |
29 |
Correct |
4 ms |
5120 KB |
answer = YES |
30 |
Correct |
4 ms |
5120 KB |
answer = NO |
31 |
Correct |
3 ms |
5120 KB |
answer = YES |
32 |
Correct |
4 ms |
5120 KB |
answer = YES |
33 |
Correct |
3 ms |
5120 KB |
answer = YES |
34 |
Correct |
4 ms |
5120 KB |
answer = YES |
35 |
Correct |
3 ms |
5120 KB |
answer = YES |
36 |
Correct |
4 ms |
5120 KB |
answer = YES |
37 |
Correct |
4 ms |
5120 KB |
answer = YES |
38 |
Correct |
4 ms |
5120 KB |
answer = YES |
39 |
Correct |
4 ms |
5248 KB |
answer = YES |
40 |
Correct |
5 ms |
5248 KB |
answer = YES |
41 |
Correct |
4 ms |
5376 KB |
answer = NO |
42 |
Correct |
5 ms |
5248 KB |
answer = YES |
43 |
Correct |
5 ms |
5248 KB |
answer = YES |
44 |
Correct |
5 ms |
5248 KB |
answer = YES |
45 |
Correct |
4 ms |
5248 KB |
answer = YES |
46 |
Correct |
4 ms |
5120 KB |
answer = YES |
47 |
Correct |
4 ms |
5248 KB |
answer = YES |
48 |
Correct |
4 ms |
5248 KB |
answer = YES |
49 |
Correct |
20 ms |
6832 KB |
answer = YES |
50 |
Correct |
17 ms |
7040 KB |
answer = YES |
51 |
Correct |
20 ms |
7216 KB |
answer = YES |
52 |
Correct |
13 ms |
6912 KB |
answer = NO |
53 |
Correct |
5 ms |
5248 KB |
answer = YES |
54 |
Correct |
7 ms |
5504 KB |
answer = YES |
55 |
Correct |
11 ms |
6012 KB |
answer = YES |
56 |
Correct |
20 ms |
6832 KB |
answer = YES |
57 |
Correct |
17 ms |
6272 KB |
answer = YES |
58 |
Correct |
17 ms |
6376 KB |
answer = YES |
59 |
Correct |
12 ms |
5888 KB |
answer = YES |
60 |
Correct |
19 ms |
6528 KB |
answer = YES |
61 |
Correct |
8 ms |
5504 KB |
answer = YES |
62 |
Correct |
79 ms |
21240 KB |
answer = NO |
63 |
Correct |
93 ms |
21368 KB |
answer = YES |
64 |
Correct |
83 ms |
21328 KB |
answer = NO |
65 |
Correct |
88 ms |
21624 KB |
answer = YES |
66 |
Correct |
6 ms |
5376 KB |
answer = YES |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5120 KB |
answer = YES |
2 |
Correct |
3 ms |
5120 KB |
answer = YES |
3 |
Correct |
3 ms |
5120 KB |
answer = YES |
4 |
Correct |
3 ms |
5120 KB |
answer = NO |
5 |
Correct |
3 ms |
5120 KB |
answer = YES |
6 |
Correct |
3 ms |
5120 KB |
answer = YES |
7 |
Correct |
3 ms |
5120 KB |
answer = YES |
8 |
Correct |
3 ms |
5120 KB |
answer = YES |
9 |
Correct |
3 ms |
5120 KB |
answer = NO |
10 |
Correct |
3 ms |
5120 KB |
answer = YES |
11 |
Correct |
3 ms |
5120 KB |
answer = YES |
12 |
Correct |
3 ms |
5120 KB |
answer = NO |
13 |
Correct |
3 ms |
5120 KB |
answer = YES |
14 |
Correct |
3 ms |
5120 KB |
answer = YES |
15 |
Correct |
3 ms |
5120 KB |
answer = YES |
16 |
Correct |
3 ms |
5120 KB |
answer = YES |
17 |
Correct |
3 ms |
5120 KB |
answer = YES |
18 |
Correct |
3 ms |
5120 KB |
answer = YES |
19 |
Correct |
3 ms |
5120 KB |
answer = YES |
20 |
Correct |
4 ms |
5120 KB |
answer = YES |
21 |
Correct |
3 ms |
5120 KB |
answer = YES |
22 |
Correct |
3 ms |
5120 KB |
answer = NO |
23 |
Correct |
3 ms |
5120 KB |
answer = NO |
24 |
Correct |
3 ms |
5120 KB |
answer = YES |
25 |
Correct |
3 ms |
5120 KB |
answer = YES |
26 |
Correct |
4 ms |
5120 KB |
answer = YES |
27 |
Correct |
4 ms |
5120 KB |
answer = YES |
28 |
Correct |
3 ms |
5120 KB |
answer = YES |
29 |
Correct |
4 ms |
5120 KB |
answer = YES |
30 |
Correct |
4 ms |
5120 KB |
answer = NO |
31 |
Correct |
3 ms |
5120 KB |
answer = YES |
32 |
Correct |
4 ms |
5120 KB |
answer = YES |
33 |
Correct |
3 ms |
5120 KB |
answer = YES |
34 |
Correct |
4 ms |
5120 KB |
answer = YES |
35 |
Correct |
3 ms |
5120 KB |
answer = YES |
36 |
Correct |
4 ms |
5120 KB |
answer = YES |
37 |
Correct |
4 ms |
5120 KB |
answer = YES |
38 |
Correct |
4 ms |
5120 KB |
answer = YES |
39 |
Correct |
4 ms |
5248 KB |
answer = YES |
40 |
Correct |
5 ms |
5248 KB |
answer = YES |
41 |
Correct |
4 ms |
5376 KB |
answer = NO |
42 |
Correct |
5 ms |
5248 KB |
answer = YES |
43 |
Correct |
5 ms |
5248 KB |
answer = YES |
44 |
Correct |
5 ms |
5248 KB |
answer = YES |
45 |
Correct |
4 ms |
5248 KB |
answer = YES |
46 |
Correct |
4 ms |
5120 KB |
answer = YES |
47 |
Correct |
4 ms |
5248 KB |
answer = YES |
48 |
Correct |
4 ms |
5248 KB |
answer = YES |
49 |
Correct |
20 ms |
6832 KB |
answer = YES |
50 |
Correct |
17 ms |
7040 KB |
answer = YES |
51 |
Correct |
20 ms |
7216 KB |
answer = YES |
52 |
Correct |
13 ms |
6912 KB |
answer = NO |
53 |
Correct |
5 ms |
5248 KB |
answer = YES |
54 |
Correct |
7 ms |
5504 KB |
answer = YES |
55 |
Correct |
11 ms |
6012 KB |
answer = YES |
56 |
Correct |
20 ms |
6832 KB |
answer = YES |
57 |
Correct |
17 ms |
6272 KB |
answer = YES |
58 |
Correct |
17 ms |
6376 KB |
answer = YES |
59 |
Correct |
12 ms |
5888 KB |
answer = YES |
60 |
Correct |
19 ms |
6528 KB |
answer = YES |
61 |
Correct |
8 ms |
5504 KB |
answer = YES |
62 |
Correct |
79 ms |
21240 KB |
answer = NO |
63 |
Correct |
93 ms |
21368 KB |
answer = YES |
64 |
Correct |
83 ms |
21328 KB |
answer = NO |
65 |
Correct |
88 ms |
21624 KB |
answer = YES |
66 |
Correct |
6 ms |
5376 KB |
answer = YES |
67 |
Correct |
163 ms |
27728 KB |
answer = YES |
68 |
Correct |
148 ms |
27624 KB |
answer = YES |
69 |
Correct |
122 ms |
27372 KB |
answer = YES |
70 |
Correct |
172 ms |
38252 KB |
answer = YES |
71 |
Correct |
124 ms |
27372 KB |
answer = YES |
72 |
Correct |
291 ms |
21736 KB |
answer = YES |
73 |
Correct |
234 ms |
21480 KB |
answer = YES |
74 |
Correct |
142 ms |
19060 KB |
answer = YES |
75 |
Correct |
92 ms |
17912 KB |
answer = NO |
76 |
Correct |
24 ms |
7200 KB |
answer = YES |
77 |
Correct |
51 ms |
9268 KB |
answer = YES |
78 |
Correct |
97 ms |
12276 KB |
answer = YES |
79 |
Correct |
239 ms |
19436 KB |
answer = YES |
80 |
Correct |
155 ms |
19188 KB |
answer = YES |
81 |
Correct |
126 ms |
23144 KB |
answer = NO |
82 |
Correct |
197 ms |
27116 KB |
answer = YES |
83 |
Correct |
225 ms |
27884 KB |
answer = YES |
84 |
Correct |
324 ms |
27996 KB |
answer = YES |
85 |
Correct |
160 ms |
27624 KB |
answer = YES |
86 |
Correct |
134 ms |
27500 KB |
answer = YES |
87 |
Correct |
92 ms |
16884 KB |
answer = NO |
88 |
Correct |
227 ms |
20488 KB |
answer = YES |
89 |
Correct |
131 ms |
14072 KB |
answer = YES |
90 |
Correct |
133 ms |
14072 KB |
answer = YES |
91 |
Correct |
141 ms |
14456 KB |
answer = YES |
92 |
Correct |
59 ms |
9720 KB |
answer = YES |
93 |
Correct |
59 ms |
9720 KB |
answer = YES |
94 |
Correct |
137 ms |
26472 KB |
answer = NO |
95 |
Correct |
83 ms |
13048 KB |
answer = NO |
96 |
Correct |
239 ms |
26744 KB |
answer = YES |
97 |
Correct |
69 ms |
26088 KB |
answer = NO |