Merge pull request #752 from stlouisp/sd2

 CPP program to find length of the longest prefix which is also suffix

Advanced data structures/Longest prefix which is also suffix.cpp

@@ -0,0 +1,54 @@
+// CPP program to find length of the
+// longest prefix which is also suffix
+#include <bits/stdc++.h>
+using namespace std;
+
+// Function to find largest prefix
+// which is also a suffix
+int largest_prefix_suffix(const std::string
+									&str)
+{
+
+int n = str.length();
+
+// if n is less than 2
+if(n < 2) {
+	return 0;
+}
+
+int len = 0;
+int i = 1;
+
+// Iterate i till n
+while(i < n)
+{
+
+	// If str[i] is equal to
+	// str[len]
+	if(str[i] == str[len])
+	{
+	++len;
+	++i;
+	}
+	else
+	{
+	i = i - len + 1;
+	len = 0;
+	}
+}
+
+// Return len
+return len>n/2? len/2:len;
+
+}
+
+// Driver code
+int main()
+{
+
+string s = "blablabla";
+
+// Function Call
+cout << largest_prefix_suffix(s);
+return 0;
+}