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package com.danielvaughan.ctci.strings;
/**
* Created with IntelliJ IDEA.
* User: dvaughan
* Date: 13/07/2013
* Time: 13:48
* To change this template use File | Settings | File Templates.
*/
public class HasAllUniqueCharacters {
public boolean hasAllUniqueCharacters(final String string)
{
if (string==null || string.length()==0)
{
return false;
}
if (string.length()==1)
{
return true;
}
String first = string.substring(0,1);
String rest = string.substring(1);
if (rest.contains(first))
{
return false;
}
else
{
return hasAllUniqueCharacters(rest);
}
}
public static void main(String [] args)
{
HasAllUniqueCharacters hauc = new HasAllUniqueCharacters();
String uniqueString = "abcdefgh";
String nonUniqueString = "abcdefab";
System.out.println(uniqueString + " " + hauc.hasAllUniqueCharacters(uniqueString));
System.out.println(nonUniqueString + " " + hauc.hasAllUniqueCharacters(nonUniqueString));
}
}
package com.danielvaughan.ctci.strings;
import java.util.HashMap;
import java.util.Map;
/**
* Created with IntelliJ IDEA.
* User: dvaughan
* Date: 13/07/2013
* Time: 14:00
* To change this template use File | Settings | File Templates.
*/
public class Permutation {
public boolean isPermutation (final String stringA, final String stringB)
{
if (stringA.length() != stringB.length())
{
return false;
}
Map<Character, Integer> aCharCount = new HashMap<Character, Integer>();
Map<Character, Integer> bCharCount = new HashMap<Character, Integer>();
for (int i=0; i<stringA.length(); i++)
{
char aChar = stringA.charAt(i);
char bChar = stringB.charAt(i);
int currentACount = aCharCount.get(aChar)==null ? 0 : aCharCount.get(aChar);
int currentBCount = bCharCount.get(bChar)==null ? 0 : bCharCount.get(bChar);
aCharCount.put(aChar, currentACount++);
bCharCount.put(bChar, currentBCount++);
}
for (Character key : aCharCount.keySet())
{
if (aCharCount.get(key) != bCharCount.get(key))
{
return false;
}
}
return true;
}
public static void main(String [] args)
{
Permutation permutation = new Permutation();
String string = "abcdefgh";
String permString = "hgfedcba" ;
String nonPermString = "abcdefab";
System.out.println(permString + " " + permutation.isPermutation(string, permString));
System.out.println(nonPermString + " " + permutation.isPermutation(string, nonPermString));
}
}
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