Submission #1096282

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096282		Zero_OP	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	137 ms	28720 KiB

palindromic

#include<bits/stdc++.h>

using namespace std;

#define sz(v) (int)v.size()
#define all(v) begin(v), end(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define dbg(v) "[" #v " = " << (v) << "]"
#define file(name) if(fopen(name".inp", "r")) {freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
#define rep(i, l, r) for(int i = (l); i < (r); ++i)
#define repd(i, r, l) for(int i = (r) - 1; i >= (l); --i)
#define FOR(i, l, r) for(int i = (l); i <= (r); ++i)
#define FORD(i, r, l) for(int i = (r); i >= (l); --i)

using ll = long long;
using vi = vector<int>;
using vl = vector<long long>;
using ld = long double;

template<typename T>
    bool minimize(T& a, const T& b){
        if(a > b){
            return a = b, true;
        }  return false;
    }

template<typename T>
    bool maximize(T& a, const T& b){
        if(a < b){
            return a = b, true;
        } return false;
    }

template<int dimension, typename T>
struct tensor : public vector<tensor<dimension - 1, T>> {
    static_assert(dimension > 0, "Dimension must be positive !\n");
    template<typename... Args>
    tensor(int n = 0, Args... args) : vector<tensor<dimension - 1, T>> (n, tensor<dimension - 1, T>(args...)) {}
};

template<typename T>
struct tensor<1, T> : public vector<T> {
    tensor(int n = 0, T val = T()) : vector<T>(n, val) {}
};

const int MAX = 1e6 + 5;
const int MOD[2] = {(int)1e9 + 9, (int)1e9 + 7};
const int BASE[2] = {31, 37};

int add(int a, int b, const int& mod){
    return a + b < mod ? a + b : a + b - mod;
}

int subtract(int a, int b, const int& mod){
    return a < b ? a - b + mod : a - b;
}

int multiply(int a, int b, const int& mod){
    return 1LL * a * b % mod;
}

int n, pw[2][MAX], h[2][MAX];
string s;

int code(char c){
    return c - 'a' + 1;
}

void init(){
    for(int i = 1; i <= n; ++i){
        for(int j : {0, 1}){
            h[j][i] = add(multiply(h[j][i - 1], BASE[j], MOD[j]), code(s[i]), MOD[j]);
        }
    }
}

int getHash(int type, int l, int r){
    return subtract(h[type][r], multiply(h[type][l - 1], pw[type][r - l + 1], MOD[type]), MOD[type]);
}

bool same(int l1, int r1, int l2, int r2){
    return getHash(0, l1, r1) == getHash(0, l2, r2) && getHash(1, l1, r1) == getHash(1, l2, r2);
}

int solve(int l, int r){
    if(l > r) return 0;
    if(l == r) return 1;

    int k = r - l + 1;
    for(int i = 1; i < k; ++i){
        if(same(l, l + i - 1, r - i + 1, r)){
            return solve(l + i, r - i) + 2;
        }
    }

    return 1;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    if(fopen("task.inp", "r")){
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);
    }

    pw[0][0] = 1;
    pw[1][0] = 1;
    FOR(i, 1, 1000000){
        pw[0][i] = multiply(pw[0][i - 1], BASE[0], MOD[0]);
        pw[1][i] = multiply(pw[1][i - 1], BASE[1], MOD[1]);
    }

    int t;
    cin >> t;
    while(t--){
        cin >> s;
        n = sz(s);
        s = '?' + s;
        init();
        cout << solve(1, n) << '\n';
    }

    return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen("task.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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