CareerCup

class Solution {
  public static void main(String[] args) {

    // test case
    int[][] input = {{1,2,3}, {9, 0}, {5}, {-4,-5,-2,-3,-1}};

    int[] out = new int[input[0].length + input[1].length + input[2].length + input[3].length];

    out = interleaveList(input);
    for (int i = 0; i < out.length; i++)
      System.out.print(out[i] + " ");
  }
  
  static public int[] interleaveList(int[][] in) {
    
    // get max_len to cover all rows
    int max_len = 0;
    int size_all = 0; // size for all elements
    for (int i = 0; i < in.length; i++) {
      if (in[i].length > max_len)
        max_len = in[i].length;
      size_all += in[i].length;
    }
    
    int[] out = new int[size_all];
    int k = 0;
    // interleave in the loop
    for (int i = 0; i < max_len; i++) {
      for (int j = 0; j < in.length; j++) {
        if (i < in[j].length) {
          out[k++] = in[j][i];
        }
      }
    }
    
    return out;
  }
}

public class Solution {

    static public void main(String[] args) {

        String a = "29023902397403472034", b = "8372283473748173";

        String out = AddVeryLargeNumbers(a, b);
        System.out.println(out);
    }

    static String AddVeryLargeNumbers(String a, String b) {

        StringBuilder out = new StringBuilder();

        int max_len = a.length() >= b.length()? a.length() : b.length();

        int i = a.length() - 1, j = b.length()-1;
        int carry = 0;

        while (max_len > 0) {

            int tmp = 0;
            if (i >= 0)
                tmp += (int) a.charAt(i) - '0';
            if (j >= 0)
                tmp += (int) b.charAt(j) - '0';
            if (carry == 1) {
                tmp += carry;
            }

            // handling carry
            if (tmp >= 10) {
                carry = 1;
                out.insert(0, tmp-10);
            } else {
                carry = 0;
                out.insert(0, tmp);
            }

            i--;
            j--;
            max_len--;
        }

        if (carry == 1)
            out.insert(0, String.valueOf(1));

        return out.toString();
    }
}

public class Main {

    public static void main(String[] args) {

        // test set
//        String[] arr = {"abcd", "cbad", "bacd"};
        String[] arr = {"abcd", "acbd", "adcb", "cdba", "bcda", "badc"};

        // convert ArrayList form as it is beneficial to handle
        ArrayList<String> input = new ArrayList<String>();
        for (int i = 0; i <arr.length; i++) {
            input.add(i, arr[i]);
        }

        // main loop
        for (int i = 0; i < input.size()-1; i++) {

            for (int j = i+1; j < input.size(); j++) {

                // Question here: any possibility that identical strings exist? (assuming no for now)

                // check with swapEven
                if (input.get(i).equals(swapEven(input.get(j)))) {
                    // remove if equivalent
                    input.remove(j);
                    j--;
                    // go back to loop
                    continue;
                }

                // check with swapOdd
                if (input.get(i).equals(swapOdd(input.get(j)))) {
                    // remove if equivalent
                    input.remove(j);
                    j--;
                    // go back to loop (no need as this is end of loop)
                    //continue;
                }
            }

        }

        System.out.println("length: " + input.size());
    }

    // swap a character at even-numbered index
    // assuming string length is 4
    static String swapEven(String in) {

        char data[] = {in.charAt(2), in.charAt(1), in.charAt(0), in.charAt(3)};
        String out = new String(data);

        return out;
    }

    // swap a character at odd-numbered index
    // assuming string length is 4
    static String swapOdd(String in) {

        char data[] = {in.charAt(0), in.charAt(3), in.charAt(2), in.charAt(1)};
        String out = new String(data);

        return out;
    }
}

public class AverageStream {

    private long[] stream;

    private double average = 0;

    // constructor
    AverageStream(long[] input) {
        stream = input;
    }

    // calculate average
    void setAverage() {
        long sum = 0;
        for (int i = 0; i < stream.length; i++) {
            // in case of overflow, set zero
            if (isOverflow(sum)) {
                sum = 0;
                average = 0;
                return;
            }

            sum += stream[i];
        }

        average = (sum/stream.length);
    }

    double getAverage() {
        return average;
    }

    boolean isOverflow(long in) {
        if (in >= -0x7FFFFFFF && in <= 0x7FFFFFFF)
            return false;
        else
            return true;
    }
}

import java.util.ArrayList;
import java.util.List;
import java.util.TreeMap;

public class Main {

    public static void main(String[] args) {

        // input setup
        List<int[]> list = new ArrayList<int[]>();

        list.add(new int[]{2,3});
        list.add(new int[]{2,4});
        list.add(new int[]{5,6});
        list.add(new int[]{8,6});
        list.add(new int[]{1,0});

        // try TreeMap as it supports sort in ascending order
        // distance and point
        TreeMap<Integer, int[]> inputs = new TreeMap<Integer, int[]>();

        // for distance, we only need relative length, so root is not required.
        for (int i = 0; i < list.size(); i++) {
            inputs.put(list.get(i)[0]*list.get(i)[0] + list.get(i)[1]*list.get(i)[1], list.get(i));
        }

        // for a given 'n', return relevant elements from the list
        int n = 3;
        ArrayList<int[]> out = new ArrayList<int[]>();
        for (int i = 0; i < n; i++) {
            out.add(list.get(i));
        }

        // check
        for (int i = 0; i < out.size(); i++) {
            System.out.println(out.get(i)[0] + ", " + out.get(i)[1]);
        }
    }
}

A code to support from 1 to 9999

public class ConvertInteger2EnglishPhrase {

    public static void main(String[] args) {

        String[] ones = {"", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};

        String[] teens = {"", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Ninteen"};

        String[] tens = {"", "Ten", "Twenty", "Thirty", "Fourty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninty"};

        String[] hundreds = new String[10];
        for (int i = 0; i < 10; i++) {
            hundreds[i] = ones[i] + " " + "Hundred";
        }

        String[] thousands = new String[10];
        for (int i = 0; i < 10; i++) {
            thousands[i] = ones[i] + " " + "Thousand";
        }

        String[][] numbers = {ones, tens, hundreds, thousands};


        int input = 117;
        String out = "";

        int len;

        int divider = 1;

        for (int j = 1; j <= 9999; j++) {

            input = j;
            out = "";

            while (input > 0) {

                if (input > 0 && input < 10) {
                    out += " " + ones[input % 10];
                    break;
                } else if (input > 10 && input < 20) {
                    out += " " + teens[input % 10];
                    break;
                } else {

                    // get # of digit
                    len = String.valueOf(input).length();

                    divider = 1;
                    for (int i = 0; i < (len - 1); i++)
                        divider *= 10;

                    int quotient = input / divider;

                    out += " " + numbers[len - 1][quotient];

                    input -= divider * quotient;
                }
            }

            System.out.println(out);
        }
    }
}

public class FinaCelebrity {

    public static void main(String[] args) {

        // initialize Person instances assuming Tom is the celebrity
        // John
        Person john = new Person("John");
        john.friendsList.add("Eric");
        john.friendsList.add("Kevin");
        john.friendsList.add("Tom");
        john.friendsList.add("Joey");

        // Eric
        Person eric = new Person("Eric");
        eric.friendsList.add("John");
        eric.friendsList.add("BM");
        eric.friendsList.add("Tom");

        // Jeff
        Person jeff = new Person("Jeff");
        jeff.friendsList.add("Amy");
        jeff.friendsList.add("Tom");

        // Tom (the celebrity who knows no one in the room, so no friends)
        Person tom = new Person("Tom");

        // add persons into people
        ArrayList<Person> people = new ArrayList<Person>();
	people.add(john);
        people.add(eric);
        people.add(jeff);

        // check if a person is the celebrity
        String name = tom.name;
        if (findCelebrity(people, john))
            System.out.println(name + " is celebrity");
        else
            System.out.println(name + " is NOT celebrity");
    }

    // find if a person is celebrity among people
    static public boolean findCelebrity(ArrayList<Person> people, Person person) {

        // check if the person doesn't know any in the room
        if (!person.friendsList.isEmpty())
            return false;

        // check if everyone know the person
        int len = people.size();
        for (int i = 0; i < len; i++) {
            if (people.get(i).name != person.name) { // skip himself
                if (!people.get(i).friendsList.contains(person.name)) // check if person is included in the friend list
                    return false;
            }
        }

        return true;
    }

    static class Person {

        ArrayList<String> friendsList = new ArrayList<String>();

        String name;

        public Person(String _name) {
            name = _name;
        }

        public boolean knowSomeone(String person) {
            if (friendsList.contains(person))
                return true;
            else
                return false;
        }
    }
}

public class checkPalindrome {

    public static void main(String[] args) {
        String input = "L*&EVe)))l";
        if (isPalindrome(input))
            System.out.println("Palindrome");
        else
            System.out.println("NO Palindrome");
    }

    static public boolean isPalindrome(String input) {
        String out = "";

        // 1) remove special character
        int len = input.length();
        for (int i = 0; i < len; i++) {
            char c = input.charAt(i);
            if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))
                out += c;
        }

        // 2) make it lowercase
        out = out.toLowerCase();

        // 3) check if palindrom. 
        // compare [i] vs [len-i-1], we dont need check the center element if it exists (in case of odd length)
        len = out.length();
        for (int i = 0; i < len/2; i++) {
            if ((out.charAt(i) != out.charAt(len-i-1))) {
                return false;
            }
        }
        return true;

    }
}