Submission #116321

#	Time	Username	Problem	Language	Result	Execution time	Memory
116321		JohnTitor	Palindromic Partitions (CEOI17_palindromic)	C++11	100 / 100	417 ms	22564 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
#define FOR(i, j, k) for(int i=(j); i<=(k); i++)
#define FFOR(i, j, k) for(int i=(j); i<(k); i++)
#define DFOR(i, j, k) for(int i=(j); i>=(k); i--)
#define bug(x) cerr<<#x<<" = "<<(x)<<'\n'
#define pb push_back
#define mp make_pair
#define bit(s, i) (((s)>>(i))&1LL)
#define mask(i) ((1LL<<(i)))
#define builtin_popcount __builtin_popcountll
#define __builtin_popcount __builtin_popcountll
using ll=long long; using ld=long double;
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); const ld pi=acos(0)*2;
template <typename T> inline void read(T &x){char c; bool nega=0; while((!isdigit(c=getchar()))&&(c!='-')); if(c=='-'){nega=1; c=getchar();} x=c-48; while(isdigit(c=getchar())) x=x*10+c-48; if(nega) x=-x;}
template <typename T> inline void writep(T x){if(x>9) writep(x/10); putchar(x%10+48);}
template <typename T> inline void write(T x){if(x<0){ putchar('-'); x=-x;} writep(x);}
template <typename T> inline void writeln(T x){write(x); putchar('\n');}
#define taskname "Palindromic"
const ll base=999727999;
string s;
ll h[1000002];
ll p[1000002];
ll get_hash(int l, int r){
    return ((h[r]-h[l-1]*p[r-l+1])%base+base)%base;
}
void solve(){
    cin>>s;
    int n=s.size();
    s='0'+s;
    FOR(i, 1, n) h[i]=(h[i-1]*131+s[i])%base;
    int ans=0;
    int l=1, r=n;
    int nl=1, nr=n;
    while(nl<nr){
        if(get_hash(l, nl)==get_hash(nr, r)){
            ans+=2;
            l=nl+1;
            r=nr-1;
            nl=l;
            nr=r;
        }
        else{
            nl++;
            nr--;
        }
    }
    if(l<=r) ans++;
    writeln(ans);
}
int main(){
    #ifdef Aria
        if(fopen(taskname".in", "r"))
            freopen(taskname".in", "r", stdin);
    #endif // Aria
    p[0]=1;
    FOR(i, 1, 1000000) p[i]=(p[i-1]*131)%base;
    int t;
    read(t);
    while(t--) solve();
}

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