#include <bits/stdc++.h>
#define vi vector<int>
#define ve vector
#define ll long long
#define vf vector<float>
#define vll vector<pair<ll,ll>>
#define ii pair<int,int>
#define pll pair<ll,ll>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 2e9+5
#define eps 1e-7
#define eps1 1e-25
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 1e5+5
#define V 450
using namespace std;
const int MOD = 1e9;
const int nax = 2e5+5;
const int lg = 20;
ll st[nax*8];
int n;
void update(int v, int l, int r, int pos, int val){
if(pos > r || pos < l) return;
if(l == r){
st[v] += val;
return;
}
int md = (l+r)/2;
update(v*2, l, md, pos, val);
update(v*2+1, md+1, r, pos, val);
st[v] = st[v*2]+st[v*2+1];
}
int query(int v, int l, int r, int i, int j){
if(i > r || j < l) return 0;
if(i <= l && r <= j) return st[v];
int md = (l+r)/2;
return query(v*2, l, md, i, j)+ query(v*2+1, md+1, r, i, j);
}
vi blck, wht;
ll test(int md){
int res = 0;
memset(st, 0, sizeof st);
vii qr;
for (int j = 0; j < n; ++j)
{
int ind = (j+md)%n;
int a = blck[j], b = wht[ind];
if(a > b) swap(a,b);
qr.pb({a,b});
}
sort(qr.begin(), qr.end());
reverse(qr.begin(), qr.end());
for(auto x : qr){
res += query(1,0,2*n-1, x.fi, x.se);
update(1,0,2*n-1, x.fi, 1);
update(1,0,2*n-1, x.se, -1);
}
return res;
}
int main() {
optimise;
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
cin >> n;
string s;
cin >> s;
for (int i = 0; i < n*2; ++i)
{
if(s[i] == 'B') blck.pb(i);
if(s[i] == 'W') wht.pb(i);
}
ll mx = 0;
int l = 0, r = n-1;
while (l < r)
{
int md = (l+r)/2;
ll a = test(md+1), b = test(md);
if(a > b){
mx = max(mx, a);
l = md+2;
} else {
mx = max(mx, b);
r = md;
}
}
cout << mx << endl;
}
Compilation message
monochrome.cpp: In function 'int main()':
monochrome.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
69 | freopen("input.txt", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
monochrome.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
70 | freopen("output.txt", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
