Submission #481602

#	Time	Username	Problem	Language	Result	Execution time	Memory
481602		Rainbowbunny	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++17	100 / 100	122 ms	3172 KiB

joi2019_ho_t3

#include <bits/stdc++.h>
using namespace std;

const int MAXN = 405;
const int INF = 1e9;

int n;
vector <int> Pos[3];
int cnt[MAXN][3];
int dp[2][MAXN][MAXN][3];

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n;
    for(int i = 1; i <= n; i++)
    {
        char c;
        cin >> c;
        for(int j = 0; j < 3; j++)
        {
            cnt[i][j] = cnt[i - 1][j];
        }
        if(c == 'R')
        {
            cnt[i][0]++;
            Pos[0].push_back(i);
        }
        else if(c == 'Y')
        {
            cnt[i][1]++;
            Pos[1].push_back(i);
        }
        else if(c == 'G')
        {
            cnt[i][2]++;
            Pos[2].push_back(i);
        }
    }
    int countcolor[3];
    for(int i = 0; i < 3; i++)
    {
        countcolor[i] = cnt[n][i];
    }
    for(int i = 0; i <= countcolor[0]; i++)
    {
        for(int j = 0; j <= countcolor[1]; j++)
        {
            for(int k = 0; k < 3; k++)
            {
                dp[0][i][j][k] = INF;
            }
        }
    }
    dp[0][0][0][0] = 0;
    dp[0][0][0][1] = 0;
    dp[0][0][0][2] = 0;
    for(int i = 1; i <= n; i++)
    {
        int c[3];
        for(c[0] = 0; c[0] <= countcolor[0]; c[0]++)
        {
            for(c[1] = 0; c[1] <= countcolor[1]; c[1]++)
            {
                c[2] = i - c[0] - c[1];
                for(int j = 0; j < 3; j++)
                {
                    dp[i & 1][c[0]][c[1]][j] = INF;
                }
                if(c[2] < 0 or c[2] > countcolor[2])
                {
                    continue;
                }               
                for(int j = 0; j < 3; j++)
                {
                    if(c[j])
                    {
                        int realpos = 0, id = Pos[j][c[j] - 1], t1 = INF;
                        for(int k = 0; k < 3; k++)
                        {
                            realpos += max(c[k], cnt[id][k]);
                            if(k != j)
                            {
                                c[j]--;
                                t1 = min(t1, dp[(i & 1) ^ 1][c[0]][c[1]][k]);
                                c[j]++;
                            }
                        }
                        dp[i & 1][c[0]][c[1]][j] = min(dp[i & 1][c[0]][c[1]][j], t1 + (realpos - i));
                    }
                }
            }
        }
    }
    int ans = INF;
    for(int i = 0; i < 3; i++)
    {
        ans = min(ans, dp[n & 1][countcolor[0]][countcolor[1]][i]);
    }
    if(ans == INF)
    {
        ans = -1;
    }
    cout << ans << '\n';
}

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