#include <bits/stdc++.h>
#define N 200005
#define int long long
using namespace std;
int arr[N];
int brr[N];
struct BIT{
int n;
vector<int> bit;
BIT(int l){
n = l+1;
bit.assign(n,0);
}
void upd(int pos){
for(;pos<n;pos+=pos&-pos){
bit[pos]++;
}
}
int get(int pos){
int ret = 0;
for(;pos>0;pos-=pos&-pos){
ret += bit[pos];
}
return ret;
}
}bt(N);
void solve(){
int n;
cin >> n;
for(int i=1;i<=n;i++){
cin >> arr[i];
brr[i] = arr[i];
}
sort(brr+1,brr+n+1);
for(int i=1;i<=n;i++){
if(brr[i] < i){
cout << -1;
return;
}
}
int ans = 0;
for(int i=n;i>=1;i--){
if(arr[i] >=i+bt.get(i)){
continue;
}
ans += i+bt.get(i) - arr[i];
bt.upd(arr[i]);
}
cout << ans;
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef Local
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t=1;
//cin>>t;
while(t--){
solve();
}
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
3 ms |
2028 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
3 ms |
2028 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |