#include <iostream>
#include <iomanip>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cassert>
#include <ctime>
#include <chrono>
#include <cstdio>
#include <random>
#include <vector>
#include <string>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <fstream>
#include <functional>
#include <complex>
using namespace std;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());
const long long INF = 1e18, MOD = 1e9 + 7, MOD2 = 998244353, LOG = 18;
const long double EPS = 1e-9, PI = acos(-1);
const long long N = 405;
long long dp[N][N][N][3];
long long after(vector<long long> idx, vector<vector<long long>>& pos, vector<vector<long long>>& cnt, long long nd)
{
long long res = 0;
for (long long i = 0; i < 3; i++)
{
if (i == nd)
{
continue;
}
if (idx[i] > 0 && pos[nd][idx[nd] - 1] < pos[i][idx[i] - 1])
{
res += cnt[i][pos[i][idx[i] - 1]] - cnt[i][pos[nd][idx[nd] - 1]];
}
}
return res;
}
void solve()
{
for (long long i = 0; i < N; i++)
{
for (long long j = 0; j < N; j++)
{
for (long long k = 0; k < N; k++)
{
for (long long lst = 0; lst < 3; lst++)
{
dp[i][j][k][lst] = INF;
}
}
}
}
for (long long lst = 0; lst < 3; lst++)
{
dp[0][0][0][lst] = 0;
}
long long n;
string s;
cin >> n >> s;
vector<vector<long long>> pos(3), cnt(3, vector<long long>(n));
for (long long i = 0; i < n; i++)
{
if (s[i] == 'R')
{
pos[0].push_back(i);
}
else if (s[i] == 'G')
{
pos[1].push_back(i);
}
else
{
pos[2].push_back(i);
}
for (long long j = 0; j < 3; j++)
{
cnt[j][i] = pos[j].size();
}
}
for (long long i = 0; i < pos[0].size() + 1; i++)
{
for (long long j = 0; j < pos[1].size() + 1; j++)
{
for (long long k = 0; k < pos[2].size() + 1; k++)
{
if (max({ i, j, k }) >= (i + j + k + 1) / 2 + 1)
{
continue;
}
vector<long long> idx = { i, j, k };
for (long long lst = 0; lst < 3; lst++)
{
for (long long pr = 0; pr < 3; pr++)
{
if (lst == pr || idx[lst] == 0)
{
continue;
}
long long ii = i, jj = j, kk = k;
if (lst == 0)
{
ii--;
}
else if (lst == 1)
{
jj--;
}
else
{
kk--;
}
if (dp[ii][jj][kk][pr] != INF)
{
long long npos = pos[lst][idx[lst] - 1] + after(idx, pos, cnt, lst);
long long dist = abs(npos - (i + j + k - 1));
dp[i][j][k][lst] = min(dp[i][j][k][lst], dp[ii][jj][kk][pr] + dist);
}
}
}
}
}
}
long long ans = INF;
for (long long lst = 0; lst < 3; lst++)
{
ans = min(ans, dp[pos[0].size()][pos[1].size()][pos[2].size()][lst]);
}
cout << (ans == INF ? -1 : ans) << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
srand(time(NULL));
int tst = 1;
//cin >> tst;
while (tst--)
{
solve();
}
return 0;
}
/*
<3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⠤⠖⠚⢉⣩⣭⡭⠛⠓⠲⠦⣄⡀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⢀⡴⠋⠁⠀⠀⠊⠀⠀⠀⠀⠀⠀⠀⠀⠀⠉⠳⢦⡀⠀⠀⠀⠀
⠀⠀⠀⠀⢀⡴⠃⢀⡴⢳⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⣆⠀⠀⠀
⠀⠀⠀⠀⡾⠁⣠⠋⠀⠈⢧⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢧⠀⠀
⠀⠀⠀⣸⠁⢰⠃⠀⠀⠀⠈⢣⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣇⠀
⠀⠀⠀⡇⠀⡾⡀⠀⠀⠀⠀⣀⣹⣆⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⠀
⠀⠀⢸⠃⢀⣇⡈⠀⠀⠀⠀⠀⠀⢀⡑⢄⡀⢀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⡇
⠀⠀⢸⠀⢻⡟⡻⢶⡆⠀⠀⠀⠀⡼⠟⡳⢿⣦⡑⢄⠀⠀⠀⠀⠀⠀⠀⠀⢸⡇
⠀⠀⣸⠀⢸⠃⡇⢀⠇⠀⠀⠀⠀⠀⡼⠀⠀⠈⣿⡗⠂⠀⠀⠀⠀⠀⠀⠀⢸⠁
⠀⠀⡏⠀⣼⠀⢳⠊⠀⠀⠀⠀⠀⠀⠱⣀⣀⠔⣸⠁⠀⠀⠀⠀⠀⠀⠀⢠⡟⠀
⠀⠀⡇⢀⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠠⠀⡇⠀⠀⠀⠀⠀⠀⠀⠀⢸⠃⠀
⠀⢸⠃⠘⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⠁⠀⠀⢀⠀⠀⠀⠀⠀⣾⠀⠀
⠀⣸⠀⠀⠹⡄⠀⠀⠈⠁⠀⠀⠀⠀⠀⠀⠀⡞⠀⠀⠀⠸⠀⠀⠀⠀⠀⡇⠀⠀
⠀⡏⠀⠀⠀⠙⣆⠀⠀⠀⠀⠀⠀⠀⢀⣠⢶⡇⠀⠀⢰⡀⠀⠀⠀⠀⠀⡇⠀⠀
⢰⠇⡄⠀⠀⠀⡿⢣⣀⣀⣀⡤⠴⡞⠉⠀⢸⠀⠀⠀⣿⡇⠀⠀⠀⠀⠀⣧⠀⠀
⣸⠀⡇⠀⠀⠀⠀⠀⠀⠉⠀⠀⠀⢹⠀⠀⢸⠀⠀⢀⣿⠇⠀⠀⠀⠁⠀⢸⠀⠀
⣿⠀⡇⠀⠀⠀⠀⠀⢀⡤⠤⠶⠶⠾⠤⠄⢸⠀⡀⠸⣿⣀⠀⠀⠀⠀⠀⠈⣇⠀
⡇⠀⡇⠀⠀⡀⠀⡴⠋⠀⠀⠀⠀⠀⠀⠀⠸⡌⣵⡀⢳⡇⠀⠀⠀⠀⠀⠀⢹⡀
⡇⠀⠇⠀⠀⡇⡸⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⠮⢧⣀⣻⢂⠀⠀⠀⠀⠀⠀⢧
⣇⠀⢠⠀⠀⢳⠇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⡎⣆⠀⠀⠀⠀⠀⠘
⢻⠀⠈⠰⠀⢸⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠰⠘⢮⣧⡀⠀⠀⠀⠀
⠸⡆⠀⠀⠇⣾⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⠆⠀⠀⠀⠀⠀⠀⠀⠙⠳⣄⡀⢢⡀
<3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3
*/
Compilation message
joi2019_ho_t3.cpp: In function 'void solve()':
joi2019_ho_t3.cpp:97:29: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
97 | for (long long i = 0; i < pos[0].size() + 1; i++)
| ~~^~~~~~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:99:33: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
99 | for (long long j = 0; j < pos[1].size() + 1; j++)
| ~~^~~~~~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:101:37: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
101 | for (long long k = 0; k < pos[2].size() + 1; k++)
| ~~^~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
361 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
361 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
446 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
361 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
