1.3_permutation_string.cpp

/*1.3 Given two strings, write a method to decide if one is a permutation of the other. 
space complexity:
time complexity:
date: 09/01/2014
*/
public class permutationString{
  public static boolean permutation(String s1, String s2){
    if(s1 ==NULL || s2 == NULL)
     return false;
    if(s1.isEmpty()&& s2.isEmpty())
     return true;
    else if(s1.isEmpty() || s2.isEmpty())
     return false;
    if(s1.length != s2.length)
     return false;
    int[] test = new int[256];
    for(char c : s1.toCharArray()){
      test[c] +=1;
    }
    for (char c : s2.toCharArray()){
      test[c]-=1;
    }
    for(int i: test){
      if(i!= 0)
      return false;
      else
      return true;
    }
  }
}