#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
const int MAXN = (1 << 15) + 7;
const int MAXM = 1e5 + 7;
int pref[MAXM];
ld dp[MAXN];
bool in[MAXN];
int n;
string s;
vi pos[20];
map<char, int> col;
int g;
void bfs(){
queue<int> q;
q.push(0);
in[0] = 1;
while(sz(q)){
int a = q.front();
q.pop();
for(int j = 0; j < g; j++){
if((a & (1 << j)) != 0){
continue;
}
for(int i = 1; i <= n; i++){
pref[i] = pref[i - 1];
if((1 << col[s[i - 1]]) & a){
pref[i]++;
}
}
int m = sz(pos[j]);
ld add = (ld)m * (m - 1) / 4;
ld sumaP = 0;
for(int i = 0; i < m; i++){
sumaP += (pref[n] - pref[pos[j][i]]);
}
add += sumaP;
ld sumaL = 0;
for(int i = 0; i < m; i++){
sumaP -= (pref[n] - pref[pos[j][i]]);
sumaL += pref[pos[j][i]];
ld akt = (ld)i * (i + 1) / 4 + (ld)(m - i - 1) * (m - i - 2) / 4;
add = min(add, akt + sumaP + sumaL);
}
if(!in[a + (1 << j)]){
dp[a + (1 << j)] = dp[a] + add;
in[a + (1 << j)];
q.push(a + (1 << j));
}else{
dp[a + (1 << j)] = min(dp[a + (1 << j)], dp[a] + add);
}
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> s;
n = sz(s);
set<char> xd;
for(auto ele : s){
xd.insert(ele);
}
g = sz(xd);
vector<char> vec;
for(auto ele : xd){
vec.pb(ele);
}
for(int i = 0; i < g; i++){
col[vec[i]] = i;
}
for(int i = 0; i < n; i++){
pos[col[s[i]]].pb(i);
}
if(g == 1){
ld ans = (ld)(n / 2) * (n / 2 - 1) / 4 + (ld)(n - n / 2) * (n - n / 2 - 1) / 4;
cout << fixed << setprecision(5) << ans << '\n';
return 0;
}
bfs();
cout << fixed << setprecision(9) << dp[(1 << g) - 1] << '\n';
return 0;
}
Compilation message
passes.cpp: In function 'void bfs()':
passes.cpp:90:32: warning: statement has no effect [-Wunused-value]
90 | in[a + (1 << j)];
| ~~~~~~~~~~~~~~~^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
found '100800.5000000000', expected '100800.5000000000', error '0.0000000000' |
2 |
Correct |
0 ms |
348 KB |
found '0.0000000000', expected '0.0000000000', error '-0.0000000000' |
3 |
Correct |
0 ms |
348 KB |
found '0.0000000000', expected '0.0000000000', error '-0.0000000000' |
4 |
Correct |
0 ms |
348 KB |
found '1.0000000000', expected '1.0000000000', error '0.0000000000' |
5 |
Correct |
0 ms |
348 KB |
found '124002.0000000000', expected '124002.0000000000', error '0.0000000000' |
6 |
Correct |
1 ms |
1560 KB |
found '772893586.0000000000', expected '772893586.0000000000', error '0.0000000000' |
7 |
Correct |
1 ms |
1308 KB |
found '1100977812.5000000000', expected '1100977812.5000000000', error '0.0000000000' |
8 |
Correct |
1 ms |
1308 KB |
found '1249950000.5000000000', expected '1249950000.5000000000', error '0.0000000000' |
9 |
Correct |
1 ms |
1308 KB |
found '1249975000.0000000000', expected '1249975000.0000000000', error '0.0000000000' |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
found '1.0000000000', expected '1.0000000000', error '0.0000000000' |
2 |
Correct |
0 ms |
344 KB |
found '1225.0000000000', expected '1225.0000000000', error '0.0000000000' |
3 |
Incorrect |
9 ms |
344 KB |
1st numbers differ - expected: '1023.0000000000', found: '1203.0000000000', error = '0.1759530792' |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
found '1.0000000000', expected '1.0000000000', error '0.0000000000' |
2 |
Correct |
0 ms |
344 KB |
found '1225.0000000000', expected '1225.0000000000', error '0.0000000000' |
3 |
Incorrect |
9 ms |
344 KB |
1st numbers differ - expected: '1023.0000000000', found: '1203.0000000000', error = '0.1759530792' |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
344 KB |
found '100800.5000000000', expected '100800.5000000000', error '0.0000000000' |
2 |
Correct |
0 ms |
348 KB |
found '0.0000000000', expected '0.0000000000', error '-0.0000000000' |
3 |
Correct |
0 ms |
348 KB |
found '0.0000000000', expected '0.0000000000', error '-0.0000000000' |
4 |
Correct |
0 ms |
348 KB |
found '1.0000000000', expected '1.0000000000', error '0.0000000000' |
5 |
Correct |
0 ms |
348 KB |
found '124002.0000000000', expected '124002.0000000000', error '0.0000000000' |
6 |
Correct |
1 ms |
1560 KB |
found '772893586.0000000000', expected '772893586.0000000000', error '0.0000000000' |
7 |
Correct |
1 ms |
1308 KB |
found '1100977812.5000000000', expected '1100977812.5000000000', error '0.0000000000' |
8 |
Correct |
1 ms |
1308 KB |
found '1249950000.5000000000', expected '1249950000.5000000000', error '0.0000000000' |
9 |
Correct |
1 ms |
1308 KB |
found '1249975000.0000000000', expected '1249975000.0000000000', error '0.0000000000' |
10 |
Correct |
0 ms |
348 KB |
found '1.0000000000', expected '1.0000000000', error '0.0000000000' |
11 |
Correct |
0 ms |
344 KB |
found '1225.0000000000', expected '1225.0000000000', error '0.0000000000' |
12 |
Incorrect |
9 ms |
344 KB |
1st numbers differ - expected: '1023.0000000000', found: '1203.0000000000', error = '0.1759530792' |
13 |
Halted |
0 ms |
0 KB |
- |