Submission #638961

#	Time	Username	Problem	Language	Result	Execution time	Memory
638961		zaneyu	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	70 ms	28412 KiB

palindromic

/*input
4
bonobo
deleted
racecar
racecars
*/
#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<long long,null_type,less_equal<long long>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=long double;
using pii=pair<int,int>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET(v,x) lower_bound(ALL(v),x)-v.begin()
const int maxn=1e6+3;
const int INF=0x3f3f3f3f;
const int MOD=1e6+3;
const ld PI=acos(-1.0l);
const ld eps=1e-6;
const ll INF64=9e18+1;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
    out<<P.f<<' '<<P.s;
    return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
    REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?" ":"");
    return out;
}
int mult(int a,int b){
    return 1LL*a*b%MOD;
}
ll mypow(ll a,ll b,ll mod){
    if(b<=0) return 1;
    a%=mod;
    ll res=1LL;
    while(b){
        if(b&1) res=(res*a)%mod;
        a=(a*a)%mod;
        b>>=1;
    }
    return res;
}
typedef unsigned long long ull;
ull pw[maxn],pf[maxn];
int n;
ull get(int l,int r){
    return (pf[r]-pf[l-1]*pw[r-l+1]);
}
void solve(){
    string s;
    cin>>s;
    n=sz(s);
    s="0"+s;
    REP1(i,n){
        pf[i]=pf[i-1]*31+(s[i]-'a'+1);
    }
    int i=1,j=n;
    int a=1,b=n;
    int ans=0;
    while(i<j){
        if(get(a,i)==get(j,b)){
            a=i+1,b=j-1;
            ans+=2;
        }
        ++i,--j;
    }
    if(a<=b) ++ans;
    cout<<ans<<'\n';
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int t;
    cin>>t;
    pw[0]=1;
    REP1(i,maxn-1) pw[i]=pw[i-1]*31;
    while(t--) solve();
}

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