제출 #1330952

#제출 시각아이디문제언어결과실행 시간메모리
1330952goldenbullPalindromic Partitions (CEOI17_palindromic)C++17
100 / 100
462 ms28028 KiB
#include<bits/stdc++.h>
#define el '\n'
using namespace std;
using ull = unsigned long long;
template<class T> using ve = vector<T>;
const int N = 1e5+7;
const int base1 = 47;
const int base2 = 107;
const int M1 = 1e9+7;
const int M2 = 1e9+9;
static int tc = 1;

int pw(int a, int b, int m) {
    int ans = 1;
    while (b) {
        if (b&1) ans=1ll*ans*a%m;
        a=1ll*a*a%m;
        b>>=1;
    }
    return ans;
}
int inv(int k, int m) { return pw(k,m-2,m); }
ull pack(int x, int y) { return 1ll*2e9*x + 1ll*y; }

struct HS {
    int n,base,M;
    ve<int> p,bp,ibp;
    void init(const string &s, int _base, int _mod) {
        n = s.size()-1;
        base = _base;
        M = _mod;
        p.resize(n+1);
        bp.resize(n+1);
        ibp.resize(n+1);
        bp[0] = 1;
        for (int i=1; i<=n; i++) {
            int d = s[i] - 'a' + 1;
            bp[i] = 1ll*bp[i-1]*base%M;
            p[i] = (p[i-1] + 1ll*bp[i]*d%M)%M;
        }
        ibp[n] = inv(bp[n],M);
        for (int i=n-1; i>=0; i--) ibp[i] = 1ll*ibp[i+1]*base%M;
    }
    int get(int l, int r) {
        return 1ll*(p[r]-p[l-1]+M)*ibp[l-1]%M;
    }
};

struct DHS {
    HS sh1, sh2;
    void init(const string &s) {
        sh1.init(s,base1,M1);
        sh2.init(s,base2,M2);
    }
    ull get(int l, int r) {
        return pack(sh1.get(l,r),sh2.get(l,r));
    }
};

int n;
string s;
DHS sh;

void solve() {
    cin>>s;
    n = s.size();
    s = '*'+s;

    sh.init(s);
    int ans = 0, j=1;
    for (int i=1; i<=n; i++) {
        ull h1 = sh.get(j,i);
        ull h2 = sh.get(n-i+1,n-j+1);
        if (h1 == h2) ans++, j=i+1;
    }
    cout << ans << el;
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (fopen("test.inp","r")) freopen("test.inp","r",stdin);
    cin>>tc;
    while (tc--) solve();
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

palindromic.cpp: In function 'int main()':
palindromic.cpp:81:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |     if (fopen("test.inp","r")) freopen("test.inp","r",stdin);
      |                                ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
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