#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;
Tree<int> T;
int n;
bool nex(int a, int b) {
auto it = next(T.find(a));
if (it != T.end() && *it == b) return 1;
return 0;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
FOR(i,1,n+1) T.insert(i);
vi v(n); F0R(i,n) cin >> v[i];
int ans = 0;
while (sz(v)) {
while (sz(v) > 1 && nex(v[sz(v)-2],v[sz(v)-1])) {
T.erase(v.back()); v.pop_back();
}
T.erase(v.back()); v.pop_back(); ans ++;
}
cout << ans;
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
408 KB |
Output is correct |
2 |
Correct |
3 ms |
624 KB |
Output is correct |
3 |
Correct |
3 ms |
624 KB |
Output is correct |
4 |
Incorrect |
2 ms |
624 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
408 KB |
Output is correct |
2 |
Correct |
3 ms |
624 KB |
Output is correct |
3 |
Correct |
3 ms |
624 KB |
Output is correct |
4 |
Incorrect |
2 ms |
624 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
408 KB |
Output is correct |
2 |
Correct |
3 ms |
624 KB |
Output is correct |
3 |
Correct |
3 ms |
624 KB |
Output is correct |
4 |
Incorrect |
2 ms |
624 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
408 KB |
Output is correct |
2 |
Correct |
3 ms |
624 KB |
Output is correct |
3 |
Correct |
3 ms |
624 KB |
Output is correct |
4 |
Incorrect |
2 ms |
624 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |