#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
int n;
vector<int> seg, v, pos;
void build(int x, int l, int r)
{
if (l + 1 == r)
{
seg[x] = v[l];
return;
}
int mid = (l + r) >> 1;
build(x << 1, l, mid), build(x << 1 | 1, mid, r);
seg[x] = max(seg[x << 1], seg[x << 1 | 1]);
}
int qry(int x, int l, int r, int ql, int qr)
{
if (ql <= l && r <= qr)
return seg[x];
int mid = (l + r) >> 1;
if (qr <= mid)
return qry(x << 1, l, mid, ql, qr);
if (ql >= mid)
return qry(x << 1 | 1, mid, r, ql, qr);
int retl = qry(x << 1, l, mid, ql, qr), retr = qry(x << 1 | 1, mid, r, ql, qr);
return max(retl, retr);
}
int ans(int x, int l, int r)
{
assert(qry(1, 0, n, l, r) == x);
if (x == 0 || l + 1 == r)
return 0;
if (pos[x] == l)
{
int rx = qry(1, 0, n, pos[x] + 1, r);
return ans(rx, pos[x] + 1, r) + 1;
}
if (pos[x] + 1 == r)
{
int lx = qry(1, 0, n, l, pos[x]);
return ans(lx, l, pos[x]) + 1;
}
int lx = qry(1, 0, n, l, pos[x]), rx = qry(1, 0, n, pos[x] + 1, r);
return max(ans(lx, l, pos[x]), ans(rx, pos[x] + 1, r)) + 1;
}
/*
4
3 4 1 2
1 2
2 3
3 4
*/
void solve()
{
cin >> n;
v.resize(n);
for (int &i : v)
cin >> i, --i;
for (int i = 1, a, b; i < n; ++i)
cin >> a >> b;
pos.resize(n);
for (int i = 0; i < n; ++i)
pos[v[i]] = i;
seg.assign(n * 4 + 10, 0);
build(1, 0, n);
cout << ans(n - 1, 0, n) + 1 << '\n';
}
/*
*/
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
344 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Incorrect |
0 ms |
348 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |