Z 函数(扩展 KMP)

Z 函数(扩展 KMP)

线性算法

---

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;
}

---

复杂度分析

---

字符串整周期