Submission #915774

#	Time	Username	Problem	Language	Result	Execution time	Memory
915774		Captain_Georgia	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	145 ms	18996 KiB

palindromic

#include <bits/stdc++.h>
 
using namespace std;
 
/// toto -> 1
 
#define pb push_back
#define pii pair<int,int>
#define pll pair<ll,ll>
#define io                      \
    ios_base::sync_with_stdio(0); \
    cin.tie(0);                   \
    cout.tie(0);
#define all(a) a.begin(),a.end()
#define rep(k,i,n) for(ll k=i;k<n;k++)
#define repp(k,i,n) for(ll k=n-1;k>=i;k--)
#define rech(k) for(char k='a';k<='z';k++)
#define SZ(a) (int)a.size()
#define MX(a) *max_element(all(a))
#define MN(a) *min_element(all(a))
#define SM(a) accumulate(all(a),0LL)
#define vi vector<int>
#define vl vector<long long>
#define vvl vector<vector<long long>>
#define vvi vector<vector<int>>
#define fii first
#define see second
 
/// toto -> 
const long long mod = 1e9 + 7 , modd = 998244353;
 
 
typedef long long ll;
 
void F1(bool res) {
    if(res) {
        cout<<"Yes\n" ;
    }
    else {
        cout<<"No\n" ;
    }
}
 
struct mint{
    ll val;
 
    mint(int64_t v = 0) {
        v %= mod;
        if (v < 0) v += mod;
        val = v;
    }
 
    mint& operator+=(const mint& other) {
        val += other.val;
        if (val >= mod) val -= mod;
        return *this;
    }
 
    mint& operator-=(const mint& other) {
        val += mod - other.val;
        if (val >= mod) val -= mod;
        return *this;
    }
 
    mint& operator*=(const mint& other) {
        val = (int64_t)val * other.val % mod;
        return *this;
    }
 
    mint& operator/=(const mint& other) {
        return *this *= other.inv();
    }
 
    friend mint operator+(mint a, const mint& b) { return a += b; }
    friend mint operator-(mint a, const mint& b) { return a -= b; }
    friend mint operator*(mint a, const mint& b) { return a *= b; }
    friend mint operator/(mint a, const mint& b) { return a /= b; }
 
    mint pow(int64_t exp) const {
        mint a = *this, res = 1;
        while (exp > 0) {
            if (exp & 1)
                res *= a;
            a *= a;
            exp >>= 1;
        }
        return res;
    }
 
    mint inv() const {
        assert(val != 0);
        return pow(mod - 2);
    }
 
    friend ostream& operator<<(ostream& os, const mint& m) {
        return os << m.val;
    }
};
 
ll bp(ll n,ll m){
    if(m == 0){
        return 1;
    }
    if(m == 1){
        return n%mod;
    }
    if(m%2==0){
        return bp(n*n%mod,m/2)%mod;
    }
    return n*bp(n,m-1)%mod;
}
 
 
/// toto -> 3
 
const int N = 2e5 + 9, M = 1e6 + 434, inf = 1e9 + 99;
const ll inff = 1e10;


void solve() {
	string s;
	cin >> s;
	int n = s.size();

	ll B = 47;
	vector<ll> p(n+1 , 0), pre(n+1 , 0);
	p[0] = 1; 
	pre[0] = 0;
	
	for (int i = 0; i < n; i++) {
		p[i+1] = (p[i] * B) % mod;
		pre[i+1] = (pre[i] * B + (s[i] - 'a' + 1)) % mod;
	}

	int l = 0, r = n, ans = 0;
	while (l < r) {
		int k = 0;
		ll hs1 = 0, hs2 = 1;
		while (hs1 != hs2) {
			k++;
			hs1 = pre[l+k] - (pre[l] * p[k]) % mod;
			hs2 = pre[r] - (pre[r - k] * p[k]) % mod;
			hs1 = (hs1 + mod)%mod;
			hs2 = (hs2 + mod)%mod;
		}
		ans ++;
		if(r - l != k) {
			ans++;
		}
		l += k;
		r -= k;
	}

	cout << ans << '\n';
}

int32_t main() {
	
	
    io;
    
    ll t=1;
       cin >> t;
    rep(_,1,t+1) {
		///cerr << "Start of test case: " << _ << "\n";
        ///cout<<"Case #"<<_<<": ";
        solve();
        ///cerr << "\n";
        ///cerr << "\n";
    }
    return 0;
 
}

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