#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define endl '\n'
#define fi first
#define se second
#define For(i, l, r) for (int i = l; i < r; i++)
#define ForE(i, l, r) for (int i = l; i <= r; i++)
#define FordE(i, l, r) for (int i = l; i >= r; i--)
#define Fora(v, a) for (auto v: a)
#define bend(a) a.begin(), a.end()
#define isz(a) ((signed)a.size())
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
using vi = vector <int>;
using vpii = vector <pii>;
using vvi = vector <vi>;
const int N = 2e5 + 5;
struct lazy_segment_tree{
int seg[4 * N], lazy[4 * N];
void build(int id, int l, int r){
if (l == r){
seg[id] = 0;
lazy[id] = 0;
return;
}
int mid = (l + r) >> 1;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
seg[id] = 0;
lazy[id] = 0;
}
void down(int id){
if (lazy[id] == 0){
return;
}
seg[id * 2] = max(seg[id * 2], lazy[id]);
lazy[id * 2] = max(lazy[id * 2], lazy[id]);
seg[id * 2 + 1] = max(seg[id * 2 + 1], lazy[id]);
lazy[id * 2 + 1] = max(lazy[id * 2 + 1], lazy[id]);
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int val){
if (v < l or r < u){
return;
}
if (u <= l and r <= v){
seg[id] = max(seg[id], val);
lazy[id] = max(lazy[id], val);
return;
}
down(id);
int mid = (l + r) >> 1;
update(id * 2, l, mid, u, v, val);
update(id * 2 + 1, mid + 1, r, u, v, val);
seg[id] = max(seg[id * 2], seg[id * 2 + 1]);
}
int get(int id, int l, int r, int u, int v){
if (v < l or r < u){
return 0;
}
if (u <= l and r <= v){
return seg[id];
}
down(id);
int mid = (l + r) >> 1;
return max(get(id * 2, l, mid, u, v), get(id * 2 + 1, mid + 1, r, u, v));
}
} seg;
int n, m;
int a[N];
int ans[N];
vi vpos[N];
set <int> stt;
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
// freopen("KEK.inp", "r", stdin);
// freopen("KEK.out", "w", stdout);
cin >> n;
ForE(i, 1, n){
cin >> a[i];
}
m = 2 * n - 1;
seg.build(1, 1, m);
ForE(i, 2, n){
if (a[i] > a[i - 1]){
seg.update(1, 1, m, a[i - 1] + 1, a[i] - 1, i);
}
else if (a[i] < a[i - 1]){
seg.update(1, 1, m, a[i] + 1, a[i - 1] - 1, i);
}
}
ForE(i, 1, m){
vpos[seg.get(1, 1, m, i, i)].emplace_back(i);
}
Fora(pos, vpos[0]){
stt.insert(pos);
}
ans[1] = a[1];
stt.erase(ans[1]);
ForE(i, 2, n){
if (a[i] > a[i - 1]){
ans[2 * i - 2] = *stt.upper_bound(a[i - 1]);
stt.erase(ans[2 * i - 2]);
ans[2 * i - 1] = *stt.upper_bound(a[i - 1]);
stt.erase(ans[2 * i - 1]);
}
else if (a[i] < a[i - 1]){
ans[2 * i - 2] = *(--stt.lower_bound(a[i - 1]));
stt.erase(ans[2 * i - 2]);
ans[2 * i - 1] = *(--stt.lower_bound(a[i - 1]));
stt.erase(ans[2 * i - 1]);
}
else{
ans[2 * i - 2] = *stt.upper_bound(a[i - 1]);
stt.erase(ans[2 * i - 2]);
ans[2 * i - 1] = *(--stt.lower_bound(a[i - 1]));
stt.erase(ans[2 * i - 1]);
}
Fora(pos, vpos[i]){
stt.insert(pos);
}
}
ForE(i, 1, m){
cout << ans[i] << ' ';
} cout << endl;
}
/*
==================================================+
INPUT: |
--------------------------------------------------|
--------------------------------------------------|
==================================================+
OUTPUT: |
--------------------------------------------------|
--------------------------------------------------|
==================================================+
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
4940 KB |
Output is correct |
2 |
Correct |
3 ms |
4940 KB |
Output is correct |
3 |
Correct |
3 ms |
4940 KB |
Output is correct |
4 |
Correct |
3 ms |
4940 KB |
Output is correct |
5 |
Correct |
3 ms |
4940 KB |
Output is correct |
6 |
Correct |
3 ms |
4940 KB |
Output is correct |
7 |
Correct |
3 ms |
4936 KB |
Output is correct |
8 |
Correct |
3 ms |
4940 KB |
Output is correct |
9 |
Correct |
5 ms |
5048 KB |
Output is correct |
10 |
Correct |
3 ms |
4940 KB |
Output is correct |
11 |
Correct |
4 ms |
5068 KB |
Output is correct |
12 |
Correct |
3 ms |
5068 KB |
Output is correct |
13 |
Correct |
4 ms |
5196 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
6 ms |
5256 KB |
Output is correct |
2 |
Correct |
7 ms |
5580 KB |
Output is correct |
3 |
Correct |
12 ms |
6092 KB |
Output is correct |
4 |
Correct |
26 ms |
7236 KB |
Output is correct |
5 |
Correct |
47 ms |
9580 KB |
Output is correct |
6 |
Correct |
82 ms |
14500 KB |
Output is correct |
7 |
Correct |
140 ms |
20908 KB |
Output is correct |