Submission #227551

#	Time	Username	Problem	Language	Result	Execution time	Memory
227551		MohamedAhmed04	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++14	100 / 100	381 ms	134904 KiB

joi2019_ho_t3

#include <bits/stdc++.h>

using namespace std ;

const short inf = 32767 ;
const int MAX = 400 + 5 ;

string s ;
vector< vector< vector< vector<short> > > >dp ;
short cnt[3][MAX] , occ[3][MAX] ;
int n ;

short solve(int idx , int cnt1 , int cnt2 , int cnt3 , int prv)
{
	if(idx == n)
		return 0 ;
	short &ret = dp[cnt1][cnt2][cnt3][prv] ;
	if(ret != -1)
		return ret ;
	ret = inf ;
	for(int i = 0 ; i <= 2 ; ++i)
	{
		if(i == prv && idx != 0)
			continue ;
		int to = -1 ;
		if(i == 0)
			to = occ[0][cnt1] ;
		if(i == 1)
			to = occ[1][cnt2] ;
		if(i == 2)
			to = occ[2][cnt3] ;
		if(to == -1)
			continue ;
		short cost = max(0 , cnt[0][to] - cnt1) + max(0 , cnt[1][to] - cnt2) + max(0 , cnt[2][to] - cnt3) , now ;
		if(i == 0)
			now = solve(idx+1 , cnt1+1 , cnt2 , cnt3 , i) ;
		if(i == 1)
			now = solve(idx+1 , cnt1 , cnt2+1 , cnt3 , i) ;
		if(i == 2)
			now = solve(idx+1 , cnt1 , cnt2 , cnt3+1 , i) ;
		if(cost > inf-now)
			continue ;
		now += cost ;
		ret = min(ret , now) ;
	}
	return ret ;
}

int main()
{
	memset(occ , -1 , sizeof(occ)) ;
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n ;
	cin>>s ;
	short cnt1 = 0 , cnt2 = 0 , cnt3 = 0 ;
	for(int i = 0 ; i < n ; ++i)
	{
		cnt[0][i] = cnt1 , cnt[1][i] = cnt2 , cnt[2][i] = cnt3 ;
		if(s[i] == 'R')
			occ[0][cnt1++] = i ;
		else if(s[i] == 'G')
			occ[1][cnt2++] = i ;
		else
			occ[2][cnt3++] = i ;
	}
	dp = vector<vector<vector<vector<short>>>>(cnt1+1, vector<vector<vector<short>>>(cnt2+1, vector<vector<short>>(cnt3+1, vector<short>(3,-1)))) ;
	short ans = solve(0 , 0 , 0 , 0 , 0) ;
	if(ans >= inf)
		ans = -1 ;
	return cout<<ans<<"\n" , 0 ;
}		

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