#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef tree<int,null_type,less<int>,rb_tree_tag,
tree_order_statistics_node_update> indexed_set;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
#define pb push_back
#define popb pop_back
#define pp pop_back
#define pf push_front
#define popf pop_front
#define all(x) (x).begin(),(x).end()
#define ff first
#define ss second
///#define int ll
int nx[4] = {0,0,1,-1}, ny[4] = {1,-1,0,0};
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);}
const int MOD = 1e9 + 7;
const int nax =1e5 + 4;
int n, g, sz = 1;
ld dp[(1 << 15)][15];
string s;
vi A[15];
vi st;
ld exp_front[nax], exp_back[nax];
void update(int i, int val)
{
i += sz;
st[i] = val;
i /= 2;
while(i)
{
st[i] = st[2 * i] + st[2 * i + 1];
i /= 2;
}
}
int query(int p, int l, int r, int i, int j)
{
if( i> j)
return 0;
if(l >= i && r <= j)
return st[p];
int m = (l+r)/2;
return query(2 * p,l,m,i,min(j,m))
+ query(2 * p + 1,m+1,r,max(i,m+1),j);
}
ld f(int mask, int b)
{
if(dp[mask][b] != -1)
return dp[mask][b];
ld rep = 0, ans = MOD;
for(auto e: A[b])
{
ld addfront = (ld)(query(1,0,sz-1,0,e));
ld addback = (ld)(query(1,0,sz - 1,e,n-1));
rep += min(exp_front[e] + addfront,exp_back[e] + addback);
}
for(auto e: A[b])
update(e,1);
if(mask == (1 << g)-1)
ans = 0;
for(int j = 0; j < g; j++)
{
if((1 << j) & mask)
continue;
ans = min(ans,f(mask + (1 << j),j));
}
for(auto e: A[b])
update(e,0);
//cout << mask << ' ' << b << ' ' << ans << ' ' << rep << '\n';
return dp[mask][b] = ans + rep;
}
void solve()
{
cin >> s;
n = s.length();
while(sz < n)
sz = (sz << 1);
st.assign(2 * sz + 1,0);
for(int i = 0; i < n ;i ++)
{
int c =s[i] - 'A';
A[c].pb(i);
g= max(g,c + 1);
}
for(int i = 0; i < (1 << g); i++)
{
for(int j = 0; j < g; j++)
dp[i][j] =-1;
}
for(int group = 0; group < g; group ++)
{
int szi = A[group].size();
for(int i =0; i < szi; i++)
{
exp_front[A[group][i]] = ((i * (i + 1))/2);
exp_front[A[group][i]] /= (i+1);
exp_back[A[group][i]] = (((szi -i - 1)*(szi - i))/2);
exp_back[A[group][i]] /= (szi - i);
//cout << A[group][i] << ' ' << exp_front[A[group][i]] << ' ' << exp_back[A[group][i]] << '\n';
}
}
ld ans = MOD;
for(int i = 0; i < g; i++)
ans = min(ans,f((1 << i),i));
cout.precision(9);
cout << fixed << ans ;
}
int32_t main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int tt = 1;
while(tt --)
solve();
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
