Submission #339703

#	Time	Username	Problem	Language	Result	Execution time	Memory
339703		nandonathaniel	Palindromic Partitions (CEOI17_palindromic)	C++14	60 / 100	920 ms	5000 KiB

palindromic

#include<bits/stdc++.h>
using namespace std;
const int MAXN=10005,MOD=1e9+7;
 
int pref[MAXN],pkt[MAXN];
map<int,int> dp[MAXN];
string s;
 
int get(int L,int R){
	if(L>R)return 0;
	return (pref[R]-((1LL*pref[L-1]*pkt[R-L+1])%MOD)+MOD)%MOD;
}

int DP(int L,int R){
	if(L>R)return 0;
	if(dp[L].count(R))return dp[L][R];
	int ret=1;
	for(int i=(R-L+1)/2;i>=1;i--){
		if(get(L,L+i-1)==get(R-i+1,R)){
			ret=max(ret,2+DP(L+i,R-i));
		}
	}
	return dp[L][R]=ret;
}
 
int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int t,n;
	cin >> t;
	while(t--){
		cin >> s;
		n=(int)s.length();
		for(int i=1;i<=n;i++)dp[i].clear();
		pkt[0]=1;
		for(int i=0;i<n;i++){
			pref[i+1]=(26LL*pref[i]+s[i]-'a')%MOD;
			pkt[i+1]=(26LL*pkt[i])%MOD;
		}
		cout << DP(1,n) << '\n';
	}
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 40