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userCompare  challenge

Posted on 2016-08-30
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Last Modified: 2016-09-02
Hi,


i am working one below challenge
http://codingbat.com/prob/p143482

i was not clear on below description

We have data for two users, A and B, each with a String name and an int id. The goal is to order the users such as for sorting. Return -1 if A comes before B, 1 if A comes after B, and 0 if they are the same. Order first by the string names, and then by the id numbers if the names are the same. Note: with Strings str1.compareTo(str2) returns an int value which is negative/0/positive to indicate how str1 is ordered to str2 (the value is not limited to -1/0/1). (On the AP, there would be two User objects, but here the code simply takes the two strings and two ints directly. The code logic is the same.)
what is A and what is B here to sort??

how below results are -1 and 1 and 0 please advise
userCompare("bb", 1, "zz", 2) → -1
userCompare("bb", 1, "aa", 2) → 1
userCompare("bb", 1, "bb", 1) → 0
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Question by:gudii9
3 Comments
 
LVL 28

Accepted Solution

by:
Bill Bach earned 250 total points
ID: 41778354
You really need to read the entire description carefully.  If you are going to be a coder, you must have a mind for details.

>what is A and what is B here to sort??
If you look at the code window on that page, you will see:
   public int userCompare(String aName, int aId, String bName, int bId)
The first two fields are the string and integer for A, and the second two fields are the string and integer for B.  You are not sorting them, but only comparing them.

>how below results are -1 and 1 and 0 please advise
In the first example, the string for A is less than the string for B, so it returns -1.
In the second example, the string for A is more than the string for B, so it returns 1.
In the third example, the string for A is the same as the string for B, so it then compares the integer fields.  The integer fields are the same, so it returns 0.

This is stated in the problem just as clearly:
Return -1 if A comes before B,
[return] 1 if A comes after B, and
[return] 0 if they are the same.
Order first by the string names, and then by the id numbers if the names are the same.
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LVL 84

Assisted Solution

by:ozo
ozo earned 250 total points
ID: 41779284
public int userCompare(String aName, int aId, String bName, int bId) {
  return (int)Math.signum(2*Math.signum(aName.compareTo(bName))+Math.signum(aId-bId));
}
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LVL 7

Author Comment

by:gudii9
ID: 41782484
public int userCompare(String aName, int aId, String bName, int bId) {
  int res=aName.compareTo(bName);
  if(aName.equals(bName)&&(aId==bId)){
    return 0;
  }
  if(res>0){
    return 1;
    
  }else if(res<0){
    return -1;
    
  }else if(aId>bId){
    return 1;
    
  }else 
    return -1;
    
  
  
}

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above also passed all tests. Any improvements or alternate approaches?
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