1-9-string-rotation Algorithm
The 1-9-string-rotation Algorithm is a technique used for rotating a given string of alphanumeric characters that include the numbers 1 to 9 by a specified number of positions. This algorithm is useful in various applications like cryptography, data manipulation, and computer programming. The primary purpose of this algorithm is to transform the input string such that each character is shifted to a new position in the output string while maintaining the original sequence of characters.
The algorithm works by following a set of steps that involve iterating over each character of the input string, determining its new position based on the specified number of rotations, and placing the character at its new position in the output string. This process is repeated for every character in the input string until the entire string has been rotated. The algorithm takes into account the specific range of characters (1-9) and ensures that the rotation wraps around the range, such that if the rotation exceeds the highest character (9), it will start again from the lowest character (1). This results in a new string with each character shifted by the specified number of positions, providing a simple yet effective method for rotating alphanumeric strings.
/**
* Cracking the coding interview 1-9
* You have a function "isSubstring" which checks whether a string is 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".
*
* Approach:
* example s1 = "waterbottle", and s2 = "erbottlewat", clearly s2 is rotation of s1.
* lets say s1 = xy ==> wat + erbottle
* similarly s2 = yx ==> erbottle + wat
* Therefore s1s1 = "waterbottlewaterbottle", clearly s2 is substring of s1s1
* So if a string is formed by rotation of another string, it will always be substring of concatenated original string to itself.
*/
#include <iostream>
#include <string>
bool isRotation( std::string s1, std::string s2 ) {
size_t len1 = s1.length();
size_t len2 = s2.length();
if ( len1 == 0 || len1 != len2 ) {
return false;
}
std::string concatS1 = s1 + s1;
if ( concatS1.find(s2) != std::string::npos ) {
return true;
} else {
return false;
}
}
int main() {
std::string s1, s2;
std::cout << "Enter string 1 : ";
std::cin >> s1;
std::cout << "Enter string 2 : ";
std::cin >> s2;
if ( isRotation(s1, s2) ) {
std::cout << "Yes! " << s2 << " is rotation of " << s1 << std::endl;
} else {
std::cout << "No! " << s2 << " is not a rotation of " << s1 << std::endl;
}
return 0;
}
