#include<bits/stdc++.h> using namespace std; #define ll long long #define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++) #define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--) #define pa pair<ll, ll> #define fi first #define se second #define bit(mask, j) ((mask >> j) & 1) const ll mod = 1e9 + 7; const ll INF = 1e9; //-------------------------------------------------------------------- ll n; string T = "RGY"; string s; const int N = 402; int f[N][N][N][3]; vector<ll> Pos[4]; ll node = 0; ll sum[4][N]; ll dp(ll i, ll j, ll k, ll last) { // if(mark[i][j][k] == 0) { // mark[i][j][k] = ++node; // } if(f[i][j][k][last] != -1) return f[i][j][k][last]; ll pos = i + j + k; if(pos == n) return 0; ll res = INF; int id[3]; id[0] = i; id[1] = j; id[2] = k; FOR(c, 0, 2) { ll sz = Pos[c].size() - 1; if(id[c] < sz && c != last) { ll idx = Pos[c][id[c] + 1]; ll cur = 0; FOR(non_c, 0, 2) { if(non_c != c) { cur += max(0LL, sum[non_c][idx] - id[non_c]); } } res = min(res, dp(i + (c == 0), j + (c == 1), k + (c == 2), c) + cur); } } return f[i][j][k][last] = res; } void hbmt() { cin >> n; cin >> s; n = s.size(); s = ' ' + s; FOR(c, 0, 2) Pos[c].push_back(0); FOR(i, 1, n) { ll c = T.find(s[i]); Pos[c].push_back(i); FOR(j, 0, 2) { sum[j][i] = sum[j][i - 1]; } sum[c][i] += 1; } memset(f, -1, sizeof f); ll val = dp(0, 0, 0, 3); if(val >= INF) cout << -1; else cout << val; } int main() { ios_base::sync_with_stdio(0); cin.tie(0);cout.tie(0); #define NAME "hbmt" if(fopen(NAME".inp", "r")) { freopen(NAME".inp", "r", stdin); freopen(NAME".out", "w", stdout); } //int t;cin>>t;while(t--) hbmt(); return 0; }

joi2019_ho_t3.cpp: In function 'int main()':
joi2019_ho_t3.cpp:75:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |                 freopen(NAME".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
joi2019_ho_t3.cpp:76:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |                 freopen(NAME".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~