Submission #1273284

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273284		trvhung	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++20	100 / 100	394 ms	780936 KiB

joi2019_ho_t3

#include <bits/stdc++.h>
// #include <ext/rope>
// #include <ext/pb_ds/assoc_container.hpp>

// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
using namespace std;

// #define   ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define            ll long long
#define           ull unsigned long long
#define            ld long double
#define            pb push_back
#define  bit(mask, i) ((mask >> i) & 1)
#define            el '\n'
#define             F first
#define             S second

template <class X, class Y> bool maximize(X &x, const Y &y) { return (x < y ? x = y, 1 : 0); }
template <class X, class Y> bool minimize(X &x, const Y &y) { return (x > y ? x = y, 1 : 0); }

const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7;
const int MULTI = 0;
const ld eps = 1e-9;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0}; // R D L U
const int ddx[4] = {-1, 1, 1, -1}, ddy[4] = {1, 1, -1, -1}; // UR DR DL UL
const char cx[4] = {'R', 'D', 'L', 'U'};
const ll base = 31;
const int nMOD = 2;
const ll mods[] = {(ll)1e9 + 10777, (ll)1e9 + 19777, (ll)1e9 + 3, (ll)1e9 + 3777};

const int N = 4e2 + 5;
int n, dp[N][N][N][3], pref[3][N], pos[3][N], cnt[3];
string s;

void solve() {
	cin >> n >> s;
	for (auto &c: s)
		if (c == 'R')
			c = 'A';
		else if (c == 'G')
			c = 'B';
		else 
			c = 'C';

	s = ' ' + s;
	for (int i = 1; i <= n; ++i)
		for (int j = 0; j < 3; ++j) {
			pref[j][i] = pref[j][i - 1];
			if (s[i] - 'A' == j) {
				pref[j][i]++;
				pos[j][++cnt[j]] = i;
			}
		}

	memset(dp, 0x3f, sizeof(dp));
	for (int i = 0; i < 3; ++i)
		dp[0][0][0][i] = 0;

	for (int i = 0; i <= cnt[0]; ++i)
		for (int j = 0; j <= cnt[1]; ++j)
			for (int k = 0; k <= cnt[2]; ++k)
				for (int pre = 0; pre < 3; ++pre)
					for (int nxt = 0; nxt < 3; ++nxt) {
						if (pre == nxt) continue;
						if ((nxt == 0 && i == cnt[0]) || (nxt == 1 && j == cnt[1]) || (nxt == 2 && k == cnt[2])) continue;

						int posPre, posNxt, posOth, oth;
						if (pre == 0) {
							posPre = pos[0][i];

							if (nxt == 1) posNxt = pos[1][j + 1], posOth = pos[2][k], oth = 2;
							else posNxt = pos[2][k + 1], posOth = pos[1][j], oth = 1;
						}
						else if (pre == 1) {
							posPre = pos[1][j];

							if (nxt == 0) posNxt = pos[0][i + 1], posOth = pos[2][k], oth = 2;
							else posNxt = pos[2][k + 1], posOth = pos[0][i], oth = 0;
						}
						else {
							posPre = pos[2][k];

							if (nxt == 0) posNxt = pos[0][i + 1], posOth = pos[1][j], oth = 1;
							else posNxt = pos[1][j + 1], posOth = pos[0][i], oth = 0;
						}

						int tmp = 0;
						tmp += max(0, pref[pre][posNxt] - pref[pre][posPre]);
						tmp += max(0, pref[oth][posNxt] - pref[oth][posOth]);
						tmp += dp[i][j][k][pre];

						if (nxt == 0)
							minimize(dp[i + 1][j][k][nxt], tmp);
						else if (nxt == 1)
							minimize(dp[i][j + 1][k][nxt], tmp);
						else
							minimize(dp[i][j][k + 1][nxt], tmp);
					}

	int res = INF;
	for (int i = 0; i < 3; ++i)
		minimize(res, dp[cnt[0]][cnt[1]][cnt[2]][i]);

	cout << (res == INF ? -1 : res);
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    if (!MULTI) solve();
    else {
        int test; cin >> test;
        while (test--) solve();
    }
    
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 55 / 55
• Subtask 3: 15 / 15
• Subtask 4: 25 / 25