#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5, LOG = 21;
int n, a[N], st[4 * N], maxRange[N];
struct SegmentTree {
int n;
vector <int> st;
SegmentTree() {}
SegmentTree(int _n) {
this -> n = _n;
st.assign(4 * n + 5, N);
}
int Left(int x) {return (x << 1);}
int Right(int x) {return (x << 1) + 1;}
void update(int id, int L, int R, int i, int j, int val) {
if (L > j || R < i) return;
if (L >= i && R <= j) {
st[id] = min(st[id], val);
return;
}
int mid = (L + R) >> 1;
update(Left(id), L, mid, i, j, val);
update(Right(id), mid + 1, R, i, j, val);
}
int get(int id, int L, int R, int i) {
if (L > i || R < i) return N;
if (L == R) {
return st[id];
}
int mid = (L + R) >> 1, res = st[id];
res = min(res, get(Left(id), L, mid, i));
res = min(res, get(Right(id), mid + 1, R, i));
return res;
}
void update(int i, int j, int val) {
update(1, 1, n, i, j, val);
}
int get(int i) {
return get(1, 1, n, i);
}
};
int main(int argc, char const *argv[])
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
maxRange[n] = n;
for (int i = n - 1; i >= 1; --i) {
if (a[i] <= a[i + 1]) maxRange[i] = maxRange[i + 1];
else maxRange[i] = i;
}
SegmentTree solver = SegmentTree(n);
solver.update(1, maxRange[1], 1);
set <int> S; S.clear(); S.insert(a[1]);
for (int i = 2; i <= n; ++i) {
int val;
set <int>::iterator it = S.lower_bound(a[i]);
if (it == S.end()) val = N;
else val = *it;
int l = i, r = maxRange[i], far = i;
while (l <= r) {
int mid = (l + r) >> 1;
if (a[mid] > val) r = mid - 1;
else l = mid + 1, far = mid;
}
solver.update(i, far, solver.get(i - 1) + 1);
S.insert(a[i]);
}
cout << solver.get(n) << endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
0 ms |
384 KB |
Output is correct |
3 |
Correct |
1 ms |
384 KB |
Output is correct |
4 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
0 ms |
384 KB |
Output is correct |
3 |
Correct |
1 ms |
384 KB |
Output is correct |
4 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
0 ms |
384 KB |
Output is correct |
3 |
Correct |
1 ms |
384 KB |
Output is correct |
4 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
384 KB |
Output is correct |
2 |
Correct |
0 ms |
384 KB |
Output is correct |
3 |
Correct |
1 ms |
384 KB |
Output is correct |
4 |
Incorrect |
1 ms |
384 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |