#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define AquA cin.tie(0);ios_base::sync_with_stdio(0);
#define fs first
#define sc second
#define p_q priority_queue
#define int long long
using namespace std;
signed main(){
AquA;
int n;
cin >> n;
string s;
cin >> s;
int ans=1e14;
vector<int> a,b;
for(int i=0;i<n;i++){
if(s[i]=='B'){
a.push_back(i);
}
if(s[i+n]=='W'){
b.push_back(i);
}
}
int nn=n;
n=a.size();
vector<int> mp(n,-1);
auto f=[&](int i){
if(mp[i]>=0){
return mp[i];
}
int xx=0;
for(int j=0;j<n;j++){
xx+=min(abs(b[j]-a[(i+j)%n]),nn-abs(b[j]-a[(i+j)%n]));
}
ans=min(ans,xx);
mp[i]=xx;
return xx;
};
int z;
if(n){
if(f(0)<f(n-1)){
z=n-1;
int l=0,r=n-1;
while(r>l){
int m=(l+r)/2;
if(f(m)<=f(z)){
r=m;
}
else{
l=m+1;
}
}
int bl=l,br=n-1;
while(br>bl+1){
int m=(bl+br)/2;
if(f(m)>f(m+1)){
bl=m;
}
else{
br=m+1;
}
}
f(bl);
f(br);
}
else{
z=0;
int l=0,r=n-1;
while(r>l){
int m=(l+r+1)/2;
if(f(m)<=f(z)){
l=m;
}
else{
r=m-1;
}
}
int bl=l,br=n-1;
while(br>bl+1){
int m=(bl+br)/2;
if(f(m)>f(m+1)){
bl=m;
}
else{
br=m+1;
}
}
f(bl);
f(br);
}
}
else{
ans=0;
}
cout << nn*(nn-1)/2-ans << "\n";
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Execution timed out |
2083 ms |
212 KB |
Time limit exceeded |
8 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Execution timed out |
2083 ms |
212 KB |
Time limit exceeded |
8 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Execution timed out |
2083 ms |
212 KB |
Time limit exceeded |
8 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
1 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Execution timed out |
2083 ms |
212 KB |
Time limit exceeded |
8 |
Halted |
0 ms |
0 KB |
- |