string/z_algorithm.hpp

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• Last update: 2025-02-21 22:14:14+09:00
• Include: #include "string/z_algorithm.hpp"

Verified with

• verify/yosupo/yosupo_zalgorithm.test.cpp

Code

vector<int> z_algorithm(const string& s) {
    int n = s.size();
    vector<int> z(n);
    z[0] = n;
    int i = 1, j = 0;
    while(i < n) {
        while(i + j < n && s[j] == s[i + j]) j++;
        z[i] = j;
        if(j == 0) { i++; continue; } 
        int k = 1;
        while(k < j && k + z[k] < j) { z[i + k] = z[k]; k++; }
        i += k; j -= k;
    }
    return z;
}

#line 1 "string/z_algorithm.hpp"
vector<int> z_algorithm(const string& s) {
    int n = s.size();
    vector<int> z(n);
    z[0] = n;
    int i = 1, j = 0;
    while(i < n) {
        while(i + j < n && s[j] == s[i + j]) j++;
        z[i] = j;
        if(j == 0) { i++; continue; } 
        int k = 1;
        while(k < j && k + z[k] < j) { z[i + k] = z[k]; k++; }
        i += k; j -= k;
    }
    return z;
}

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