#include <bits/stdc++.h>
using namespace std;
#define int long long
#define inf 0x3F3F3F3F3F3F3F3F
struct BIT
{
int n;
vector<int> ft;
void init(int N)
{
n = N + 10;
ft.assign(n + 10, 0);
}
void add(int pos, int val)
{
for (pos = pos + 5; pos <= n; pos += pos & -pos) ft[pos] += val;
}
int get(int pos, int res = 0)
{
for (pos = pos + 5; pos > 0; pos -= pos & -pos) res += ft[pos];
return res;
}
};
struct SegTree
{
int sz;
vector<array<int, 2>> st;
vector<int> lz;
void init(int n)
{
st.assign((n + 1) << 2, {-inf, inf});
lz.assign((n + 1) << 2, -1);
}
void relax(int l, int r, int x)
{
if (lz[x] == -1) return;
st[x][0] = st[x][1] = lz[x];
if (l == r)
{
lz[x] = -1;
return;
}
lz[2*x] = lz[2*x + 1] = lz[x];
lz[x] = -1;
}
array<int, 2> combine(array<int, 2> a, array<int, 2> b)
{
return {max(a[0], b[0]), min(a[1], b[1])};
}
void make(int l, int r, int x, int lx, int rx, int val)
{
if (lx > rx) return;
relax(l, r, x);
if (l > rx || r < lx) return;
if (l >= lx && r <= rx)
{
lz[x] = val;
relax(l, r, x);
return;
}
int mid = (l + r) >> 1;
make(l, mid, 2*x, lx, rx, val);
make(mid + 1, r, 2*x + 1, lx, rx, val);
st[x] = combine(st[2*x], st[2*x + 1]);
}
array<int, 2> get(int l, int r, int x, int lx, int rx)
{
if (lx > rx) return {-inf, inf};
if (l > rx || r < lx) return {-inf, inf};
relax(l, r, x);
if (l >= lx && r <= rx) return st[x];
int mid = (l + r) >> 1;
return combine(get(l, mid, 2*x, lx, rx), get(mid + 1, r, 2*x + 1, lx, rx));
}
};
const int MXN = 1e5 + 5;
const int LOG = 18;
int n;
vector<int> adj[MXN];
int sz[MXN], p[LOG][MXN], dep[MXN], head[MXN], col[MXN];
int in[MXN], out[MXN], tim;
void _init(int a)
{
sz[a] = 1;
int mx = 0;
for (int i = 0; i < adj[a].size(); i++)
{
dep[adj[a][i]] = dep[a] + 1;
_init(adj[a][i]);
sz[a] += sz[adj[a][i]];
if (sz[adj[a][i]] > sz[adj[a][mx]]) mx = i;
}
if (!adj[a].empty()) swap(adj[a][mx], adj[a][0]);
}
void dfs(int a)
{
in[a] = ++tim;
for (int i = 0; i < adj[a].size(); i++)
{
if (!i) head[adj[a][i]] = head[a];
else head[adj[a][i]] = adj[a][i];
dfs(adj[a][i]);
}
out[a] = tim;
}
BIT ft;
SegTree st;
void upd(int a, int val)
{
while (a != 1)
{
if (head[a] == a)
{
col[a] = val;
a = p[0][a];
}
else
{
st.make(1, n, 1, in[head[a]] + 1, in[a], val);
a = head[a];
}
}
col[1] = val;
}
vector<array<int, 2>> tmp;
int handle(int l, int r)
{
int ans = 0;
while (r >= l)
{
int lx = l, rx = r;
int val = st.get(1, n, 1, r, r)[0];
while (lx < rx)
{
int mid = (lx + rx) >> 1;
array<int, 2> x = st.get(1, n, 1, mid, r);
if (x[0] == x[1]) rx = mid;
else lx = mid + 1;
}
ans += ft.get(val - 1) * (r - lx + 1);
tmp.push_back({val, r - lx + 1});
ft.add(val, r - lx + 1);
r = lx - 1;
}
return ans;
}
int getans(int a)
{
int res = 0;
while (a != 1)
{
if (head[a] == a)
{
res += ft.get(col[a] - 1);
ft.add(col[a], 1);
tmp.push_back({col[a], 1});
a = p[0][a];
}
else
{
res += handle(in[head[a]] + 1, in[a]);
a = head[a];
}
}
res += ft.get(col[1] - 1);
while (!tmp.empty())
{
ft.add(tmp.back()[0], -tmp.back()[1]);
tmp.pop_back();
}
return res;
}
vector<int> mp;
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n;
st.init(n);
for (int i = 1; i <= n; i++) cin >> col[i], mp.push_back(col[i]);
sort(mp.begin(), mp.end());
mp.resize(unique(mp.begin(), mp.end()) - mp.begin());
for (int i = 1; i <= n; i++) col[i] = lower_bound(mp.begin(), mp.end(), col[i]) - mp.begin() + 1;
ft.init(mp.size());
vector<array<int, 2>> e;
head[1] = 1;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
e.push_back({u, v});
p[0][v] = u;
adj[u].push_back(v);
}
p[0][1] = 1;
for (int i = 1; i < LOG; i++) for (int j = 1; j <= n; j++) p[i][j] = p[i - 1][p[i - 1][j]];
_init(1);
dfs(1);
st.make(1, n, 1, 1, 1, col[1]);
for (int i = 0; i < e.size(); i++)
{
cout << getans(e[i][0]) << '\n';
upd(e[i][1], col[e[i][1]]);
}
}
Compilation message
construction.cpp: In function 'void _init(long long int)':
construction.cpp:93:20: 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]
93 | for (int i = 0; i < adj[a].size(); i++)
| ~~^~~~~~~~~~~~~~~
construction.cpp: In function 'void dfs(long long int)':
construction.cpp:106:20: 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]
106 | for (int i = 0; i < adj[a].size(); i++)
| ~~^~~~~~~~~~~~~~~
construction.cpp: In function 'int main()':
construction.cpp:212:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
212 | for (int i = 0; i < e.size(); i++)
| ~~^~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
13144 KB |
Output is correct |
2 |
Correct |
2 ms |
13148 KB |
Output is correct |
3 |
Correct |
2 ms |
17244 KB |
Output is correct |
4 |
Correct |
2 ms |
19292 KB |
Output is correct |
5 |
Correct |
2 ms |
17244 KB |
Output is correct |
6 |
Correct |
3 ms |
17240 KB |
Output is correct |
7 |
Correct |
3 ms |
17244 KB |
Output is correct |
8 |
Correct |
3 ms |
17500 KB |
Output is correct |
9 |
Correct |
3 ms |
17376 KB |
Output is correct |
10 |
Correct |
3 ms |
17500 KB |
Output is correct |
11 |
Correct |
3 ms |
15256 KB |
Output is correct |
12 |
Correct |
3 ms |
17240 KB |
Output is correct |
13 |
Correct |
3 ms |
17400 KB |
Output is correct |
14 |
Correct |
3 ms |
17244 KB |
Output is correct |
15 |
Correct |
2 ms |
17244 KB |
Output is correct |
16 |
Correct |
3 ms |
17240 KB |
Output is correct |
17 |
Correct |
3 ms |
17240 KB |
Output is correct |
18 |
Correct |
2 ms |
17244 KB |
Output is correct |
19 |
Correct |
3 ms |
17244 KB |
Output is correct |
20 |
Correct |
3 ms |
17240 KB |
Output is correct |
21 |
Correct |
3 ms |
17240 KB |
Output is correct |
22 |
Correct |
3 ms |
17392 KB |
Output is correct |
23 |
Correct |
2 ms |
17244 KB |
Output is correct |
24 |
Correct |
2 ms |
17244 KB |
Output is correct |
25 |
Correct |
3 ms |
17244 KB |
Output is correct |
26 |
Correct |
3 ms |
17244 KB |
Output is correct |
27 |
Correct |
3 ms |
17244 KB |
Output is correct |
28 |
Correct |
3 ms |
17244 KB |
Output is correct |
29 |
Correct |
3 ms |
17244 KB |
Output is correct |
30 |
Correct |
3 ms |
17240 KB |
Output is correct |
31 |
Correct |
3 ms |
17244 KB |
Output is correct |
32 |
Correct |
3 ms |
17244 KB |
Output is correct |
33 |
Correct |
3 ms |
17244 KB |
Output is correct |
34 |
Correct |
3 ms |
17244 KB |
Output is correct |
35 |
Correct |
3 ms |
17244 KB |
Output is correct |
36 |
Correct |
2 ms |
17244 KB |
Output is correct |
37 |
Correct |
2 ms |
17244 KB |
Output is correct |
38 |
Correct |
2 ms |
17244 KB |
Output is correct |
39 |
Correct |
3 ms |
17396 KB |
Output is correct |
40 |
Correct |
3 ms |
17244 KB |
Output is correct |
41 |
Correct |
3 ms |
17244 KB |
Output is correct |
42 |
Correct |
2 ms |
17244 KB |
Output is correct |
43 |
Correct |
3 ms |
17388 KB |
Output is correct |
44 |
Correct |
2 ms |
17456 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
13144 KB |
Output is correct |
2 |
Correct |
2 ms |
13148 KB |
Output is correct |
3 |
Correct |
2 ms |
17244 KB |
Output is correct |
4 |
Correct |
2 ms |
19292 KB |
Output is correct |
5 |
Correct |
2 ms |
17244 KB |
Output is correct |
6 |
Correct |
3 ms |
17240 KB |
Output is correct |
7 |
Correct |
3 ms |
17244 KB |
Output is correct |
8 |
Correct |
3 ms |
17500 KB |
Output is correct |
9 |
Correct |
3 ms |
17376 KB |
Output is correct |
10 |
Correct |
3 ms |
17500 KB |
Output is correct |
11 |
Correct |
3 ms |
15256 KB |
Output is correct |
12 |
Correct |
3 ms |
17240 KB |
Output is correct |
13 |
Correct |
3 ms |
17400 KB |
Output is correct |
14 |
Correct |
3 ms |
17244 KB |
Output is correct |
15 |
Correct |
2 ms |
17244 KB |
Output is correct |
16 |
Correct |
3 ms |
17240 KB |
Output is correct |
17 |
Correct |
3 ms |
17240 KB |
Output is correct |
18 |
Correct |
2 ms |
17244 KB |
Output is correct |
19 |
Correct |
3 ms |
17244 KB |
Output is correct |
20 |
Correct |
3 ms |
17240 KB |
Output is correct |
21 |
Correct |
3 ms |
17240 KB |
Output is correct |
22 |
Correct |
3 ms |
17392 KB |
Output is correct |
23 |
Correct |
2 ms |
17244 KB |
Output is correct |
24 |
Correct |
2 ms |
17244 KB |
Output is correct |
25 |
Correct |
3 ms |
17244 KB |
Output is correct |
26 |
Correct |
3 ms |
17244 KB |
Output is correct |
27 |
Correct |
3 ms |
17244 KB |
Output is correct |
28 |
Correct |
3 ms |
17244 KB |
Output is correct |
29 |
Correct |
3 ms |
17244 KB |
Output is correct |
30 |
Correct |
3 ms |
17240 KB |
Output is correct |
31 |
Correct |
3 ms |
17244 KB |
Output is correct |
32 |
Correct |
3 ms |
17244 KB |
Output is correct |
33 |
Correct |
3 ms |
17244 KB |
Output is correct |
34 |
Correct |
3 ms |
17244 KB |
Output is correct |
35 |
Correct |
3 ms |
17244 KB |
Output is correct |
36 |
Correct |
2 ms |
17244 KB |
Output is correct |
37 |
Correct |
2 ms |
17244 KB |
Output is correct |
38 |
Correct |
2 ms |
17244 KB |
Output is correct |
39 |
Correct |
3 ms |
17396 KB |
Output is correct |
40 |
Correct |
3 ms |
17244 KB |
Output is correct |
41 |
Correct |
3 ms |
17244 KB |
Output is correct |
42 |
Correct |
2 ms |
17244 KB |
Output is correct |
43 |
Correct |
3 ms |
17388 KB |
Output is correct |
44 |
Correct |
2 ms |
17456 KB |
Output is correct |
45 |
Correct |
3 ms |
17500 KB |
Output is correct |
46 |
Correct |
9 ms |
16284 KB |
Output is correct |
47 |
Correct |
8 ms |
18008 KB |
Output is correct |
48 |
Correct |
8 ms |
18008 KB |
Output is correct |
49 |
Correct |
11 ms |
18524 KB |
Output is correct |
50 |
Correct |
11 ms |
18524 KB |
Output is correct |
51 |
Correct |
11 ms |
18524 KB |
Output is correct |
52 |
Correct |
13 ms |
18368 KB |
Output is correct |
53 |
Correct |
13 ms |
18256 KB |
Output is correct |
54 |
Correct |
13 ms |
18268 KB |
Output is correct |
55 |
Correct |
12 ms |
18264 KB |
Output is correct |
56 |
Correct |
13 ms |
18264 KB |
Output is correct |
57 |
Correct |
9 ms |
18060 KB |
Output is correct |
58 |
Correct |
9 ms |
18012 KB |
Output is correct |
59 |
Correct |
9 ms |
18056 KB |
Output is correct |
60 |
Correct |
10 ms |
18012 KB |
Output is correct |
61 |
Correct |
14 ms |
18388 KB |
Output is correct |
62 |
Correct |
14 ms |
18268 KB |
Output is correct |
63 |
Correct |
14 ms |
18268 KB |
Output is correct |
64 |
Correct |
6 ms |
16024 KB |
Output is correct |
65 |
Correct |
7 ms |
18012 KB |
Output is correct |
66 |
Correct |
8 ms |
20100 KB |
Output is correct |
67 |
Correct |
8 ms |
18012 KB |
Output is correct |
68 |
Correct |
10 ms |
18272 KB |
Output is correct |
69 |
Correct |
14 ms |
18516 KB |
Output is correct |
70 |
Correct |
12 ms |
18268 KB |
Output is correct |
71 |
Correct |
12 ms |
18268 KB |
Output is correct |
72 |
Correct |
8 ms |
18012 KB |
Output is correct |
73 |
Correct |
8 ms |
18160 KB |
Output is correct |
74 |
Correct |
13 ms |
18268 KB |
Output is correct |
75 |
Correct |
12 ms |
18288 KB |
Output is correct |
76 |
Correct |
12 ms |
18268 KB |
Output is correct |
77 |
Correct |
14 ms |
18016 KB |
Output is correct |
78 |
Correct |
11 ms |
18008 KB |
Output is correct |
79 |
Correct |
11 ms |
18232 KB |
Output is correct |
80 |
Correct |
10 ms |
18012 KB |
Output is correct |
81 |
Correct |
13 ms |
18220 KB |
Output is correct |
82 |
Correct |
13 ms |
18264 KB |
Output is correct |
83 |
Correct |
12 ms |
18012 KB |
Output is correct |
84 |
Correct |
12 ms |
18260 KB |
Output is correct |
85 |
Correct |
12 ms |
18224 KB |
Output is correct |
86 |
Correct |
14 ms |
18008 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
13144 KB |
Output is correct |
2 |
Correct |
2 ms |
13148 KB |
Output is correct |
3 |
Correct |
2 ms |
17244 KB |
Output is correct |
4 |
Correct |
2 ms |
19292 KB |
Output is correct |
5 |
Correct |
2 ms |
17244 KB |
Output is correct |
6 |
Correct |
3 ms |
17240 KB |
Output is correct |
7 |
Correct |
3 ms |
17244 KB |
Output is correct |
8 |
Correct |
3 ms |
17500 KB |
Output is correct |
9 |
Correct |
3 ms |
17376 KB |
Output is correct |
10 |
Correct |
3 ms |
17500 KB |
Output is correct |
11 |
Correct |
3 ms |
15256 KB |
Output is correct |
12 |
Correct |
3 ms |
17240 KB |
Output is correct |
13 |
Correct |
3 ms |
17400 KB |
Output is correct |
14 |
Correct |
3 ms |
17244 KB |
Output is correct |
15 |
Correct |
2 ms |
17244 KB |
Output is correct |
16 |
Correct |
3 ms |
17240 KB |
Output is correct |
17 |
Correct |
3 ms |
17240 KB |
Output is correct |
18 |
Correct |
2 ms |
17244 KB |
Output is correct |
19 |
Correct |
3 ms |
17244 KB |
Output is correct |
20 |
Correct |
3 ms |
17240 KB |
Output is correct |
21 |
Correct |
3 ms |
17240 KB |
Output is correct |
22 |
Correct |
3 ms |
17392 KB |
Output is correct |
23 |
Correct |
2 ms |
17244 KB |
Output is correct |
24 |
Correct |
2 ms |
17244 KB |
Output is correct |
25 |
Correct |
3 ms |
17244 KB |
Output is correct |
26 |
Correct |
3 ms |
17244 KB |
Output is correct |
27 |
Correct |
3 ms |
17244 KB |
Output is correct |
28 |
Correct |
3 ms |
17244 KB |
Output is correct |
29 |
Correct |
3 ms |
17244 KB |
Output is correct |
30 |
Correct |
3 ms |
17240 KB |
Output is correct |
31 |
Correct |
3 ms |
17244 KB |
Output is correct |
32 |
Correct |
3 ms |
17244 KB |
Output is correct |
33 |
Correct |
3 ms |
17244 KB |
Output is correct |
34 |
Correct |
3 ms |
17244 KB |
Output is correct |
35 |
Correct |
3 ms |
17244 KB |
Output is correct |
36 |
Correct |
2 ms |
17244 KB |
Output is correct |
37 |
Correct |
2 ms |
17244 KB |
Output is correct |
38 |
Correct |
2 ms |
17244 KB |
Output is correct |
39 |
Correct |
3 ms |
17396 KB |
Output is correct |
40 |
Correct |
3 ms |
17244 KB |
Output is correct |
41 |
Correct |
3 ms |
17244 KB |
Output is correct |
42 |
Correct |
2 ms |
17244 KB |
Output is correct |
43 |
Correct |
3 ms |
17388 KB |
Output is correct |
44 |
Correct |
2 ms |
17456 KB |
Output is correct |
45 |
Correct |
3 ms |
17500 KB |
Output is correct |
46 |
Correct |
9 ms |
16284 KB |
Output is correct |
47 |
Correct |
8 ms |
18008 KB |
Output is correct |
48 |
Correct |
8 ms |
18008 KB |
Output is correct |
49 |
Correct |
11 ms |
18524 KB |
Output is correct |
50 |
Correct |
11 ms |
18524 KB |
Output is correct |
51 |
Correct |
11 ms |
18524 KB |
Output is correct |
52 |
Correct |
13 ms |
18368 KB |
Output is correct |
53 |
Correct |
13 ms |
18256 KB |
Output is correct |
54 |
Correct |
13 ms |
18268 KB |
Output is correct |
55 |
Correct |
12 ms |
18264 KB |
Output is correct |
56 |
Correct |
13 ms |
18264 KB |
Output is correct |
57 |
Correct |
9 ms |
18060 KB |
Output is correct |
58 |
Correct |
9 ms |
18012 KB |
Output is correct |
59 |
Correct |
9 ms |
18056 KB |
Output is correct |
60 |
Correct |
10 ms |
18012 KB |
Output is correct |
61 |
Correct |
14 ms |
18388 KB |
Output is correct |
62 |
Correct |
14 ms |
18268 KB |
Output is correct |
63 |
Correct |
14 ms |
18268 KB |
Output is correct |
64 |
Correct |
6 ms |
16024 KB |
Output is correct |
65 |
Correct |
7 ms |
18012 KB |
Output is correct |
66 |
Correct |
8 ms |
20100 KB |
Output is correct |
67 |
Correct |
8 ms |
18012 KB |
Output is correct |
68 |
Correct |
10 ms |
18272 KB |
Output is correct |
69 |
Correct |
14 ms |
18516 KB |
Output is correct |
70 |
Correct |
12 ms |
18268 KB |
Output is correct |
71 |
Correct |
12 ms |
18268 KB |
Output is correct |
72 |
Correct |
8 ms |
18012 KB |
Output is correct |
73 |
Correct |
8 ms |
18160 KB |
Output is correct |
74 |
Correct |
13 ms |
18268 KB |
Output is correct |
75 |
Correct |
12 ms |
18288 KB |
Output is correct |
76 |
Correct |
12 ms |
18268 KB |
Output is correct |
77 |
Correct |
14 ms |
18016 KB |
Output is correct |
78 |
Correct |
11 ms |
18008 KB |
Output is correct |
79 |
Correct |
11 ms |
18232 KB |
Output is correct |
80 |
Correct |
10 ms |
18012 KB |
Output is correct |
81 |
Correct |
13 ms |
18220 KB |
Output is correct |
82 |
Correct |
13 ms |
18264 KB |
Output is correct |
83 |
Correct |
12 ms |
18012 KB |
Output is correct |
84 |
Correct |
12 ms |
18260 KB |
Output is correct |
85 |
Correct |
12 ms |
18224 KB |
Output is correct |
86 |
Correct |
14 ms |
18008 KB |
Output is correct |
87 |
Correct |
21 ms |
19416 KB |
Output is correct |
88 |
Correct |
62 ms |
23660 KB |
Output is correct |
89 |
Correct |
274 ms |
38216 KB |
Output is correct |
90 |
Correct |
267 ms |
38348 KB |
Output is correct |
91 |
Correct |
312 ms |
38252 KB |
Output is correct |
92 |
Correct |
459 ms |
47216 KB |
Output is correct |
93 |
Correct |
442 ms |
47564 KB |
Output is correct |
94 |
Correct |
434 ms |
47304 KB |
Output is correct |
95 |
Correct |
518 ms |
43252 KB |
Output is correct |
96 |
Correct |
533 ms |
43688 KB |
Output is correct |
97 |
Correct |
522 ms |
43692 KB |
Output is correct |
98 |
Correct |
525 ms |
43672 KB |
Output is correct |
99 |
Correct |
531 ms |
41928 KB |
Output is correct |
100 |
Correct |
370 ms |
38080 KB |
Output is correct |
101 |
Correct |
410 ms |
38348 KB |
Output is correct |
102 |
Correct |
407 ms |
38640 KB |
Output is correct |
103 |
Correct |
389 ms |
38392 KB |
Output is correct |
104 |
Correct |
639 ms |
41808 KB |
Output is correct |
105 |
Correct |
545 ms |
41816 KB |
Output is correct |
106 |
Correct |
600 ms |
41928 KB |
Output is correct |
107 |
Correct |
200 ms |
36812 KB |
Output is correct |
108 |
Correct |
215 ms |
36808 KB |
Output is correct |
109 |
Correct |
292 ms |
37320 KB |
Output is correct |
110 |
Correct |
444 ms |
45772 KB |
Output is correct |
111 |
Correct |
549 ms |
43100 KB |
Output is correct |
112 |
Correct |
477 ms |
42440 KB |
Output is correct |
113 |
Correct |
497 ms |
40588 KB |
Output is correct |
114 |
Correct |
348 ms |
38088 KB |
Output is correct |
115 |
Correct |
332 ms |
37032 KB |
Output is correct |
116 |
Correct |
562 ms |
40652 KB |
Output is correct |
117 |
Correct |
459 ms |
40136 KB |
Output is correct |
118 |
Correct |
464 ms |
38856 KB |
Output is correct |
119 |
Correct |
466 ms |
38600 KB |
Output is correct |
120 |
Correct |
495 ms |
38600 KB |
Output is correct |
121 |
Correct |
461 ms |
37836 KB |
Output is correct |
122 |
Correct |
438 ms |
37580 KB |
Output is correct |
123 |
Correct |
572 ms |
39628 KB |
Output is correct |
124 |
Correct |
532 ms |
38992 KB |
Output is correct |
125 |
Correct |
556 ms |
38604 KB |
Output is correct |
126 |
Correct |
547 ms |
38716 KB |
Output is correct |
127 |
Correct |
525 ms |
37832 KB |
Output is correct |
128 |
Correct |
493 ms |
37560 KB |
Output is correct |