src/String/Manacher.hpp

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• Last update: 2020-03-29 16:30:46+09:00
• Include: #include "src/String/Manacher.hpp"

Code

template <class T> vector<int> manacher(const vector<T>& s) {
    vector<int> R(s.size());
    int i = 0, j = 0;
    while (i < s.size()) {
        while (i - j >= 0 && i + j < s.size() && s[i - j] == s[i + j]) ++j;
        R[i] = j;
        int k = 1;
        while (i - k >= 0 && i + k < s.size() && k + R[i - k] < j) R[i + k] = R[i - k], ++k;
        i += k;
        j -= k;
    }
    return R;
}

struct Manacher {
    vector<int> a;
    template <class T> Manacher(const vector<T>& s, T DUMMY = -1) {
        int m = s.size() * 2 - 1;
        vector<T> t(m, DUMMY);
        for (int i = 0; i < s.size(); i++) {
            t[i * 2] = s[i];
        }
        a = manacher(t);
    }
    Manacher(const string& s, char DUMMY = '$') {
        int m = s.size() * 2 - 1;
        vector<char> t(m, DUMMY);
        for (int i = 0; i < s.size(); i++) {
            t[i * 2] = s[i];
        }
        a = manacher(t);
    }

    // [l, r)が回文かどうか
    bool is_palindrome(int l, int r) { return a[l + r - 1] >= r - l; }
};

#line 1 "src/String/Manacher.hpp"
template <class T> vector<int> manacher(const vector<T>& s) {
    vector<int> R(s.size());
    int i = 0, j = 0;
    while (i < s.size()) {
        while (i - j >= 0 && i + j < s.size() && s[i - j] == s[i + j]) ++j;
        R[i] = j;
        int k = 1;
        while (i - k >= 0 && i + k < s.size() && k + R[i - k] < j) R[i + k] = R[i - k], ++k;
        i += k;
        j -= k;
    }
    return R;
}

struct Manacher {
    vector<int> a;
    template <class T> Manacher(const vector<T>& s, T DUMMY = -1) {
        int m = s.size() * 2 - 1;
        vector<T> t(m, DUMMY);
        for (int i = 0; i < s.size(); i++) {
            t[i * 2] = s[i];
        }
        a = manacher(t);
    }
    Manacher(const string& s, char DUMMY = '$') {
        int m = s.size() * 2 - 1;
        vector<char> t(m, DUMMY);
        for (int i = 0; i < s.size(); i++) {
            t[i * 2] = s[i];
        }
        a = manacher(t);
    }

    // [l, r)が回文かどうか
    bool is_palindrome(int l, int r) { return a[l + r - 1] >= r - l; }
};

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