From 5c830ee9eba42d4fd474932364ff3434e04e3af8 Mon Sep 17 00:00:00 2001
From: Ashish Gupta <ashish123456.gupta@gmail.com>
Date: Fri, 26 Jun 2020 22:07:01 +0530
Subject: [PATCH] Create String Rotation (Booth's Algorithm).cpp

---
 String Rotation (Booth's Algorithm).cpp | 30 +++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 String Rotation (Booth's Algorithm).cpp

diff --git a/String Rotation (Booth's Algorithm).cpp b/String Rotation (Booth's Algorithm).cpp
new file mode 100644
index 0000000..b1aef79
--- /dev/null
+++ b/String Rotation (Booth's Algorithm).cpp	
@@ -0,0 +1,30 @@
+//Returns the lexicographically least rotation of string
+
+string least_rotation(string s)
+{
+	s += s;
+	vector<int> f(s.size(), -1);
+	int k = 0;
+	for(int j = 1; j < s.size(); j++)
+	{
+		char sj = s[j];
+		int i = f[j - k - 1];
+		while(i != -1 && sj != s[k + i + 1])
+		{
+			if(sj < s[k + i + 1])
+				k = j - i - 1;
+			i = f[i];
+		}
+		if(sj != s[k + i + 1])
+		{
+			if(sj < s[k])
+				k = j;
+			f[j - k] = -1;
+		}
+		else
+			f[j - k] = i + 1;
+	}
+	return s.substr(k, s.size() / 2);
+}
+
+//Problem 1: https://www.codechef.com/BIT32020/problems/BIT3B