Amazon Interview Question: Assume you have a method isSubstring which checks if one word is a substr

Let say you have two string s1 and s2 ,write code to check if s2 is a rotation of s1 using only one call to isSubstring(eg. "WaterBottle" is a rotation of "erbottlewat").

Approach First:

lets take s1 into two parts x and y in rotation.

s1= xy = waterbottle

x= wat

y=erbottle

s2=yx=erbottlewat

Solution:

public boolean isRotation(String s1, String s2) { int len =s1.length(); if(len == s2.length() && len > 0) { String s1s1=s1+s1; return isSubstring(s1s1,s2); } return false; }

Amazon Interview Question............................................... :)

#DataStructure #String #CoreJava