#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const int N = 200010;
vector <int> c[26];
struct Segtree{
int tree[4*N];
Segtree(){
for(int i = 0;i < 4*N;i++) tree[i] = 0;
}
int join(int a, int b){
return a+b;
}
void update(int node, int l, int r, int pos, int val){
if(l == r){
tree[node] += val;
return;
}
int mid= (l+r)/2;
if(l <= pos and pos <= mid) update(2*node, l, mid, pos, val);
else update(2*node+1, mid+1, r, pos, val);
tree[node] = join(tree[2*node], tree[2*node+1]);
return;
}
int query(int node, int l, int r, int tl, int tr){
if(l > tr or tl > r) return 0;
if(l <= tl and tr <= r) return tree[node];
int mid = (tl+tr)/2;
return join(query(2*node, l, r, tl , mid), query(2*node+1, l, r, mid+1, tr));
}
}seg;
vector <int> srt;
int tam[26];
int main(){
int n;
cin>> n;
string s;
cin >> s;
vector <int> v1, v2;
for(int i = 0;i < 2*n;i++){
c[s[i]-'a'].push_back(i+1);
}
for(int i = 0;i < 26;i++){
tam[i] = c[i].size();
tam[i] /= 2;
tam[i]--;
}
for(int i = 2*n;i > 0;i--){
if(tam[s[i-1]-'a'] < 0) continue;
c[s[i-1]-'a'].pop_back();
v2.push_back(i);
v1.push_back(c[s[i-1]-'a'][tam[s[i-1]-'a']]);
tam[s[i-1]-'a']--;
}
reverse(v1.begin(), v1.end());
reverse(v2.begin(), v2.end());
for(auto x : v1) srt.push_back(x);
for(auto x : v2) srt.push_back(x);
int res = 0;
for(auto x : srt){
//cout << x << ' ';
res += seg.query(1,x, 2*n, 1, 2*n);
seg.update(1, 1, 2*n, x, 1);
}
cout << res << endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3416 KB |
Output is correct |
2 |
Correct |
10 ms |
4756 KB |
Output is correct |
3 |
Correct |
19 ms |
6248 KB |
Output is correct |
4 |
Incorrect |
32 ms |
6760 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3416 KB |
Output is correct |
2 |
Correct |
10 ms |
4756 KB |
Output is correct |
3 |
Correct |
19 ms |
6248 KB |
Output is correct |
4 |
Incorrect |
32 ms |
6760 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3416 KB |
Output is correct |
2 |
Correct |
10 ms |
4756 KB |
Output is correct |
3 |
Correct |
19 ms |
6248 KB |
Output is correct |
4 |
Incorrect |
32 ms |
6760 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3420 KB |
Output is correct |
2 |
Correct |
1 ms |
3420 KB |
Output is correct |
3 |
Correct |
1 ms |
3420 KB |
Output is correct |
4 |
Correct |
2 ms |
3420 KB |
Output is correct |
5 |
Correct |
1 ms |
3568 KB |
Output is correct |
6 |
Correct |
1 ms |
3420 KB |
Output is correct |
7 |
Correct |
1 ms |
3420 KB |
Output is correct |
8 |
Correct |
1 ms |
3420 KB |
Output is correct |
9 |
Correct |
1 ms |
3388 KB |
Output is correct |
10 |
Correct |
2 ms |
3420 KB |
Output is correct |
11 |
Correct |
1 ms |
3568 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
3416 KB |
Output is correct |
2 |
Correct |
10 ms |
4756 KB |
Output is correct |
3 |
Correct |
19 ms |
6248 KB |
Output is correct |
4 |
Incorrect |
32 ms |
6760 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |