Submission #344384

#	Time	Username	Problem	Language	Result	Execution time	Memory
344384		prasanth30	Miners (IOI07_miners)	C++14	92 / 100	1604 ms	201064 KiB

miners

#include <bits/stdc++.h>
using namespace std;
#define int long long int
const int INF=1e18;
//dp[i][a][b][c][d] ith position, a,b first mine c,d second mine
int to_int(char c){
	if(c=='M')return 1;
	if(c=='F')return 2;
	return 3;
}
inline void solve(){
	int n;cin>>n;
	string s;cin>>s;
	s=' '+s;
	int dp[n+1][4][4][4][4]={0};
	
	int ans=0;
	int freq[4];
	freq[1]=freq[2]=freq[3]=0;
	freq[0]=INF;
	freq[to_int(s[1])]++;
	for(int i=1;i<=n;i++){
		//freq[to_int(s[i])]++;
		for(int a=0;a<4;a++){
			for(int b=0;b<4;b++){
				for(int c=0;c<4;c++){
					//dp[i][s[i][a][b][c]
					for(int d=0;d<4;d++){
						dp[i][a][b][c][d]=-INF;
						//cout<<"dp["<<i<<"]["<<a<<"]["<<b<<"]["<<c<<"]["<<d<<"]->"<<dp[i][a][b][c][d]<<"\n";
						//ans=max(ans,dp[n][a][b][c][d]);
					}
				}
			}
		}
	}
	dp[1][to_int(s[1])][0][0][0]=1;
	dp[1][0][0][to_int(s[1])][0]=1;
	for(int i=2;i<=n;i++){
		freq[to_int(s[i])]++;
		for(int a=0;a<4;a++){
			for(int b=0;b<4;b++){
				for(int c=0;c<4;c++){
					//dp[i][s[i][a][b][c]
					for(int d=0;d<4;d++){
						
						if(a==0&&d!=0)continue;
						if(b==0&&c!=0)continue;
						// 1 1 2 2
						//
						--freq[a];
						--freq[b];
						--freq[c];
						--freq[d];
						if(freq[a]<0||freq[b]<0||freq[c]<0||freq[d]<0){
							++freq[a];
							++freq[b];
							++freq[c];
							++freq[d];
							continue;
						}
						++freq[a];
						++freq[b];
						++freq[c];
						++freq[d];
						set<int> ss;
						for(int x:{to_int(s[i]),a,d}){
							if(x!=0)ss.insert(x);
						}
						dp[i][to_int(s[i])][a][b][c]=
							max(dp[i-1][a][d][b][c]+(int)ss.size(),
						dp[i][to_int(s[i])][a][b][c]);
						dp[i][b][c][to_int(s[i])][a]=
							max(dp[i-1][b][c][a][d]+(int)ss.size(),dp[i][b][c][to_int(s[i])][a]);
						//ans=max(ans,dp[i][b][c][to_int(s[i])][a]);
						//ans=max(ans,dp[i][to_int(s[i])][a][b][c]);
						
					}
				}
			}
		}
		
	}
	//for(int i=1;i<=n;i++){
		//freq[to_int(s[i])]++;
		for(int a=0;a<4;a++){
			for(int b=0;b<4;b++){
				for(int c=0;c<4;c++){
					//dp[i][s[i][a][b][c]
					for(int d=0;d<4;d++){
						//cout<<"dp["<<i<<"]["<<a<<"]["<<b<<"]["<<c<<"]["<<d<<"]->"<<dp[i][a][b][c][d]<<"\n";
						ans=max(ans,dp[n][a][b][c][d]);
					}
				}
			}
		}
	//}
	cout<<ans;
}
signed main() {
	cin.tie(NULL)->sync_with_stdio(false);
	cout.tie(NULL);
	solve();
}

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 7 / 7
• Subtask 7: 8 / 8
• Subtask 8: 8 / 8
• Subtask 9: 8 / 8
• Subtask 10: 8 / 8
• Subtask 11: 8 / 8
• Subtask 12: 0 / 8