#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
#define y1 YONE
#define free freeee
#define lcm llcm
typedef unsigned long long ull;
using namespace std;
const int N=5e5+5,M=1e6+3;
int a[N],n,dp[N][3];
bool vis[N][3];
int rec(int i,int j){
//cout<<i<<' '<<j<<endl;
if (i==n+1) return 0;
if (vis[i][j+1]) return dp[i][j+1];
dp[i][j+1]=INT_MAX;
vis[i][j+1]=1;
if (a[i]>=j) dp[i][j+1]=min(dp[i][j+1],rec(i+1,a[i]));
if (a[i]<j){
if (a[i+1]==a[i]) dp[i][j+1]=min(dp[i][j+1],rec(i+2,1)+1);
else return dp[i][j+1]=INT_MAX;
}
if (a[i]==j && a[i]==-1) dp[i][j+1]=min(dp[i][j+1],rec(i+1,1)+1);
return dp[i][j+1];
}
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
cin>>n;
for (int i=1;i<=n;i++) cin>>a[i];
int x=rec(2,a[1]);
if (x>=INT_MAX) x=-1;
cout<<x<<endl;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4444 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4444 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
4440 KB |
Output is correct |
2 |
Incorrect |
1 ms |
4444 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |