Z-Algorithm
(src/string/Z_Algorithm.hpp)

• View this file on GitHub
• Last update: 2023-01-12 22:28:24+09:00
• Include: #include "src/string/Z_Algorithm.hpp"

概要

Verified with

• test/yosupo/zalgorithm.test.cpp

Code

#pragma once
#include <algorithm>
#include <vector>

template <typename T> std::vector<int> Z_Algorithm(const T& s) {
    int n = s.size();
    std::vector<int> z(n);
    z[0] = n;
    for (int i = 1, j = 0; i < n;) {
        while (i + j < n and s[j] == s[i + j]) j++;
        z[i] = j;
        if (j == 0) {
            i++;
            continue;
        }
        int k = 1;
        while (i + k < n and k + z[k] < j) z[i + k] = z[k], k++;
        i += k;
        j -= k;
    }
    return z;
}

template <typename T> std::vector<int> LCP(const T& s, const T& t) {
    T u(s);
    u.insert(u.begin(), t.begin(), t.end());
    std::vector<int> z = Z_Algorithm(u);
    for (int& i : z) i = std::min(i, (int)t.size());
    return std::vector<int>(z.begin() + t.size(), z.end());
}

#line 2 "src/string/Z_Algorithm.hpp"
#include <algorithm>
#include <vector>

template <typename T> std::vector<int> Z_Algorithm(const T& s) {
    int n = s.size();
    std::vector<int> z(n);
    z[0] = n;
    for (int i = 1, j = 0; i < n;) {
        while (i + j < n and s[j] == s[i + j]) j++;
        z[i] = j;
        if (j == 0) {
            i++;
            continue;
        }
        int k = 1;
        while (i + k < n and k + z[k] < j) z[i + k] = z[k], k++;
        i += k;
        j -= k;
    }
    return z;
}

template <typename T> std::vector<int> LCP(const T& s, const T& t) {
    T u(s);
    u.insert(u.begin(), t.begin(), t.end());
    std::vector<int> z = Z_Algorithm(u);
    for (int& i : z) i = std::min(i, (int)t.size());
    return std::vector<int>(z.begin() + t.size(), z.end());
}

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