Z 函数(扩展 KMP)

Posted 2022-04-15 Harris-H

Z 函数(扩展 KMP)

线性算法

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Code

// C++ Version
vector<int> z_function(string s) 
  int n = (int)s.length();
  vector<int> z(n);
  for (int i = 1, l = 0, r = 0; i < n; ++i) 
    if (i <= r && z[i - l] < r - i + 1) 
      z[i] = z[i - l];
     else 
      z[i] = max(0, r - i + 1);
      while (i + z[i] < n && s[z[i]] == s[i + z[i]]) ++z[i];
    
    if (i + z[i] - 1 > r) l = i, r = i + z[i] - 1;
  
  return z;

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复杂度分析

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字符串整周期