From 9df9b5de3c3881bdb7cfc6bb278c6461cec8b2b0 Mon Sep 17 00:00:00 2001
From: Ariel <ariel@arielherself.xyz>
Date: Thu, 18 Jan 2024 14:34:46 +0800
Subject: [PATCH] Update include.hh

---
 include.hh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include.hh b/include.hh
index 4572501..671eb55 100644
--- a/include.hh
+++ b/include.hh
@@ -136,4 +136,14 @@ vector<int> kmp(string s, string t) {  // find all t in s
   }
   return v;
 }
+int period(string s) {  // find the length of shortest recurring period
+    int n = s.length();
+    auto z = calc_z(s);
+    for (int i = 1; i <= n / 2; ++i) {
+        if (n % i == 0 && z[i] == n - i) {
+            return i;
+        }
+    }
+    return n;
+}
 /////////////////////////////////////////////////////////