Submission #161906

#	Time	Username	Problem	Language	Result	Execution time	Memory
161906		impri	스탬프 수집 (JOI16_ho_t2)	C++14	100 / 100	17 ms	7716 KiB

2016_ho_t2

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int n;
string s;
ll dp[100001][3];
char joi[4];
ll get(int a,int b){
if(b==0)return 1;
if(a>=n)return 0;
if(dp[a][b]>=0)return dp[a][b];
if(joi[b]==s[a])return dp[a][b]=get(a+1,b)+get(a+1,b-1);
return dp[a][b]=get(a+1,b);

}
int main()
{  cout <<fixed;cout.precision(12);cin.tie(0);
   ios_base::sync_with_stdio(false);
   memset(dp,-1,sizeof(dp));
   cin >> n;
   cin >> s;
   joi[1]='I';
   joi[2]='O';
   joi[3]='J';
   ll res=get(0,3);
   ll add=get(0,2);
   joi[2]='J';
   joi[1]='O';
   memset(dp,-1,sizeof(dp));
   add=max(add,get(0,2));
   int jnum=0;
   int inum=0;
   for(int i=0;i<n;i++)
    if(s[i]=='I')inum++;
   for(int i=0;i<n;i++){
     if(s[i]=='J')jnum++;
     if(s[i]=='I')inum--;
     add=max(add,1LL*jnum*inum);
   }
   cout << res+add;
}

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 50 / 50