Submission #1264688

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264688		uzukishinobu	Palindromic Partitions (CEOI17_palindromic)	C++20	100 / 100	157 ms	19536 KiB

palindromic

#include <bits/stdc++.h>
#define int long long
using namespace std;
int a;
string s;
int h[1000005];
int h1[1000005];
int mu[1000005];
int base=31;
int mod=1e9+7;
int gethash(int l,int r){
    return (h[r]-h[l-1]*mu[r-l+1]%mod +mod)%mod;
}

void solve(){
    cin >> s;
    a=s.size();
    s='#'+s;
    mu[0]=1;
    h[0]=0;
    for (int i=1;i<=a;i++){
         h[i]=(h[i-1]*base+ (s[i]-'a'+1))%mod;
         mu[i]=(mu[i-1]*base)%mod;
    }
    int l=1,r=a;
    int l1=1,r1=a;
    int ans=0;
    while (l<r){
        if (gethash(l1,l)==gethash(r,r1)){
            ans+=2;
            l1=l+1;
            r1=r-1;
        }
        l++;
        r--;
    }
    ans+=(l1<=r1);
    cout << ans << "\n";
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while (t--){
         solve();
    }
    return 0;
}

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