Submission #783199

#	Time	Username	Problem	Language	Result	Execution time	Memory
783199		borisAngelov	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++17	60 / 100	528 ms	766580 KiB

joi2019_ho_t3

#include <bits/stdc++.h>

using namespace std;

const int maxn = 405;
const int inf = 1e9;

int n;
string s;

vector<int> pos[3];

int preffix[maxn][3];

int dp[maxn][maxn][maxn][3];

int decode(char c)
{
    if (c == 'R')
    {
        return 0;
    }

    if (c == 'G')
    {
        return 1;
    }

    return 2;
}

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n >> s;
    s = '#' + s;

    for (int i = 1; i <= n; ++i)
    {
        int curr = decode(s[i]);

        for (int j = 0; j < 3; ++j)
        {
            preffix[i][j] = preffix[i - 1][j];
        }

        ++preffix[i][curr];
        pos[curr].push_back(i);
    }

    for (int i = 0; i <= n; ++i)
    {
        for (int j = 0; j <= n; ++j)
        {
            for (int k = 0; k <= n; ++k)
            {
                for (int p = 0; p <= 2; ++p)
                {
                    dp[i][j][k][p] = inf;
                }
            }
        }
    }

    dp[0][0][0][0] = 0;
    dp[0][0][0][1] = 0;
    dp[0][0][0][2] = 0;

    int cnt0 = preffix[n][0];
    int cnt1 = preffix[n][1];
    int cnt2 = preffix[n][2];

    for (int i = 0; i <= cnt0; ++i)
    {
        for (int j = 0; j <= cnt1; ++j)
        {
            for (int k = 0; k <= cnt2; ++k)
            {
                if (i != 0)
                {
                    int curr_min = min(dp[i - 1][j][k][1], dp[i - 1][j][k][2]);
                    int cost = max(0, preffix[pos[0][i - 1]][1] - j) + max(0, preffix[pos[0][i - 1]][2] - k);
                    dp[i][j][k][0] = min(dp[i][j][k][0], curr_min + cost);
                }

                if (j != 0)
                {
                    int curr_min = min(dp[i][j - 1][k][0], dp[i][j - 1][k][2]);
                    int cost = max(0, preffix[pos[1][j - 1]][0] - i) + max(0, preffix[pos[1][j - 1]][2] - k);
                    dp[i][j][k][1] = min(dp[i][j][k][1], curr_min + cost);
                }

                if (k != 0)
                {
                    int curr_min = min(dp[i][j][k - 1][0], dp[i][j][k - 1][1]);
                    int cost = max(0, preffix[pos[2][k - 1]][0] - i) + max(0, preffix[pos[2][k - 1]][1] - j);
                    dp[i][j][k][2] = min(dp[i][j][k][2], curr_min + cost);
                }
            }
        }
    }

    int ans = min(dp[cnt0][cnt1][cnt2][0], min(dp[cnt0][cnt1][cnt2][1], dp[cnt0][cnt1][cnt2][2]));

    if (ans == inf)
    {
        cout << -1 << endl;
    }
    else
    {
        cout << ans << endl;
    }

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 55 / 55
• Subtask 3: 0 / 15
• Subtask 4: 0 / 25