1169. Invalid Transactions

The following leetcode exercise is one to die for.

A transaction is possibly invalid if:

• the amount exceeds $1000, or;
• if it occurs within (and including) 60 minutes of another transaction with the same name in a different city.

Each transaction string transactions[i] consists of comma separated values representing the name, time (in minutes), amount, and city of the transaction.

Given a list of transactions, return a list of transactions that are possibly invalid. You may return the answer in any order.

Example 1:

Input: transactions = ["alice,20,800,mtv","alice,50,100,beijing"]
Output: ["alice,20,800,mtv","alice,50,100,beijing"]
Explanation: The first transaction is invalid because the second transaction occurs within a difference of 60 minutes, have the same name and is in a different city. Similarly the second one is invalid too.

Example 2:

Input: transactions = ["alice,20,800,mtv","alice,50,1200,mtv"]
Output: ["alice,50,1200,mtv"]

Example 3:

Input: transactions = ["alice,20,800,mtv","bob,50,1200,mtv"]
Output: ["bob,50,1200,mtv"]

Constraints:

• transactions.length <= 1000
• Each transactions[i] takes the form "{name},{time},{amount},{city}"
• Each {name} and {city} consist of lowercase English letters, and have lengths between 1 and 10.
• Each {time} consist of digits, and represent an integer between 0 and 1000.
• Each {amount} consist of digits, and represent an integer between 0 and 2000.

Solution:

class Solution {
    public List<String> invalidTransactions(String[] transactions) {
        List<String> invalidList=new ArrayList<String>();
if(transactions == null || transactions.length <0 ) return invalidList;
        boolean[] isInvalid=new boolean[transactions.length];
        sortTransactions(transactions);
        for(int i=0; i < transactions.length;i++){
            checkifInvalid(transactions,isInvalid,i );
            if(isInvalid[i] ){ invalidList.add(transactions[i]);  }
        }
        return invalidList;
    }  
    
    public void sortTransactions(String[] transactions){
        Arrays.sort(transactions, (a, b) -> {
            String[] aArr = a.split(",");
            String[] bArr = b.split(",");
//compare name
            int temp = aArr[0].compareTo(bArr[0]);
            if (temp != 0) {
                return temp;
            } else {
                //compare time
                temp = Integer.compare(Integer.parseInt(aArr[1]), Integer.parseInt(bArr[1]));
                if (temp != 0) {
                    return temp;
                } else {
                    //compare place
                    temp = aArr[3].compareTo(bArr[3]);
                    if (temp != 0) {
                        return temp;
                    }
                }
            }
            //compare amount
            return Integer.compare(Integer.parseInt(aArr[2]), Integer.parseInt(bArr[2]));
        });        
    }
    
    
    
    public void checkifInvalid(String[] transactions, boolean[] isInvalid, int pos ){
        if(isInvalid[pos]) return ;
        if(isInvalidPrice(transactions,pos ) ) isInvalid[pos]=true;
        boolean validIsFound=false;
        while(!validIsFound && pos +1 < transactions.length ){
            if( (getName(transactions[pos]).equals( getName(transactions[pos+1]) )) &&
               (!(getCity(transactions[pos]).equals( getCity(transactions[pos+1])))) &&
                ( (getTime(transactions[pos+1]) - getTime(transactions[pos])) <61   )
                    ){
                //we found two invalids
                isInvalid[pos] = true;
                    isInvalid[pos+1] = true;
            }else{
                //next is valid. stop
                validIsFound=true;
            }
            pos++;
        }
        
    }
    
    public boolean isInvalidPrice(String[] transactions, int pos){
        return getAmmount(transactions[pos]) > 1000; 
    }
    
    
    //get name
    public String getName(String sentence){
        String[] components = sentence.split(",");
        return components[0];
    }
    
    //get time
    public int getTime(String sentence){
        String[] components = sentence.split(",");
        return Integer.parseInt(components[1]);
    }
    
    //get ammount
    public int getAmmount(String sentence){
        String[] components = sentence.split(",");
        return Integer.parseInt(components[2]);
    } 
    
    //get city
    public String getCity(String sentence){
        String[] components = sentence.split(",");
        return components[3];
    }
    
}