Assume you have a method isSubstring which checks if one word is a substring of another. Given two strings, s1 and s2, write code to check if s2 is a rotation of s1 using only one call to isSubstring (i.e., “waterbottle” is a rotation of “erbottlewat”).
Implement a method to perform basic string compression using the counts of repeated characters. For example, the string aabcccccaaa would become a2b1c5a3. If the “compressed” string would not become smaller than the original string, your method should return the original string.
Write a method to replace all spaces in a string with ‘%20’. You may assume that the string has sufficient space at the end of the string to hold the additional characters, and that you are given the “true” length of the string. (Note: if implementing in Java, please use a character array so that you can perform this operation in place.)
EXAMPLE
Input: “Mr John Smith ”
Output: “Mr%20John%20Smith”
Given two strings, write a method to decide if one is a permutation of the other.
Implement a function void reverse(char* str) in C or C++ which reverses a null-terminated string.
Implement an algorithm to determine if a string has all unique characters. What if you cannot use additional data structures?