#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define time(code) {auto _s = chrono::high_resolution_clock::now(); code;cerr << (chrono::high_resolution_clock::now() - _s).count() / 1e9 << '\n';}
inline ll exp_inv(ll x) {
return x * (x-1);
}
int main() {
cin.tie(0)->sync_with_stdio(0);
char a = 'A';
string s; cin >> s;
const int G = 15, N = 1e5;
int n = s.size();
if (n == 1) {
cout << "0\n";
return 0;
}
ll suml[G][G][N];
ll sumr[G][G][N];
ll cr[G][N];
ll cl[G][N];
int cnt[G]{};
vector ix(G, vector<int>());
time(({
for (int c1 = 0; c1 < G; c1++) {
for (int c2 = 0; c2 < G; c2++) {
ll res = 0, cur = 0;
for (int i = 0; i < n; i++) {
if (s[i] == c1+a)
res += cur;
else if (s[i] == c2+a)
cur++;
suml[c1][c2][i] = res;
}
}
}
for (int c1 = 0; c1 < G; c1++) {
for (int c2 = 0; c2 < G; c2++) {
ll res = 0, cur = 0;
for (int i = n-1; i >= 0; i --) {
if (s[i] == c1+a)
res += cur;
else if (s[i] == c2+a)
cur++;
sumr[c1][c2][i] = res;
}
}
}
for (int j = 0; j < G; j++) {
int c = 0;
for (int i = 0; i < n;i ++) {
if (s[i] == j+a)
c++;
cl[j][i] = c;
}
}
for (int j = 0; j < G; j++) {
int c = 0;
for (int i = n-1; i >= 0; i--) {
if (s[i] == j+a)
c++;
cr[j][i] = c;
}
}
for (int i = 0; i < n; i++)
cnt[s[i] - a]++;
for (int i = 0; i < G; i++)
ix[i].reserve(cnt[i]);
for (int i = 0; i < n ;i++)
ix[s[i] - a].push_back(i);
}));
ll memo[1<<G];
memo[(1<<G)-1] = 0;
for (int used = (1<<G)-1-1; used >= 0; used--) {
ll& res = memo[used];
res = 1e18;
for (int i = 0 ;i < G; i++) {
if (used&1<<i) continue;
auto f = [&](int j) {
ll sum = 0;
for (int k = 0; k < G; k++) {
int c2 = k;
if (used>>c2&1) {
if (j) sum += suml[i][c2][j-1];
if (j <n)sum += sumr[i][c2][j];
}
}
return sum * 4 + (j < n ? exp_inv(cr[i][j]) : 0) + (j ? exp_inv(cl[i][j-1]) : 0);
};
int l = -1, r = (int)ix[i].size()-2;
while (l < r-1) {
int m = (l+r) / 2;
ll a = f(ix[i][m]), b = f(ix[i][m+1]);
if (a == b) break;
else if (a < b) r = m;
else l = m;
}
for (int j = max(l-1, 0); j < min((int)ix[i].size(), 3 + max(0, r)); j++) {
res = min(res, f(ix[i][j]) + memo[used |1<<i]);
}
}
};
ll ans;
ans = memo[0];
cout << ans / 4;
if (ans%4 == 1) cout << ".25";
if (ans%4 == 2) cout << ".5";
if (ans%4== 3) cout << ".75";
cout << endl;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
163 ms |
376268 KB |
1st numbers differ - expected: '100800.5000000000', found: '250000000000000000.0000000000', error = '2480146427844.1000976562' |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
156 ms |
376204 KB |
1st numbers differ - expected: '1.0000000000', found: '250000000000000000.0000000000', error = '250000000000000000.0000000000' |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
156 ms |
376204 KB |
1st numbers differ - expected: '1.0000000000', found: '250000000000000000.0000000000', error = '250000000000000000.0000000000' |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
163 ms |
376268 KB |
1st numbers differ - expected: '100800.5000000000', found: '250000000000000000.0000000000', error = '2480146427844.1000976562' |
| 2 |
Halted |
0 ms |
0 KB |
- |
