Using queue to rearrange every other integer-CodePudding

I'm trying to figure out how to take in an integer and rearrange them so that every alternating character is saved (So the [1, 2, 3, 4, 5, 6] would return [1, 4, 2, 5, 3, 6]). I think a queue would be the best to use for this problem so here's what I have so far. It returns [3, 1, 4, 5, 2, 6], but I'm not sure how I can get it to return the alternating form above :

import java.util.*;
public class everyOtherInteger {
public static void main(String[] args) {

    Queue <Integer> sort = new LinkedList<Integer>();
    String s = "123456";    

    for (int i = 0; i < s.length(); i  ) {
        sort.add(Integer.parseInt(s.charAt(i)   ""));

        if (i%2 == 0) {
            int a = sort.remove();
            sort.add(a);
        }
        else {

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

}

CodePudding user response：

Just build the list differently. No queue required.

You can add half the numbers at the start, the add the rest in-between each.

List<Integer> nums = new ArrayList<>();

Scanner sc = new Scanner(System.in);
int limit = sc.nextInt(); // 6
int value = 1;
for (int i = 0; i < limit / 2; i  ) {
  nums.add(value  );
}
for (int i = 1; i < limit; i =2) {
  nums.add(i, value  );
}
System.out.println(nums); // [1, 4, 2, 5, 3, 6]

CodePudding user response：

I would just add them one after the other in a single loop. The second element is simply the current one plus the offset where the offset is half the array length.

read in the number as a string.
and work with the character array of digits.

Scanner input = new Scanner(System.in);
String val = input.next();
List<Integer> result  =new ArrayList<>();

char[] digits = val.toCharArray();
int half = digits.length/2;
for(int i = 0; i < half; i  ) {
    result.add(digits[i]-'0');
    result.add(digits[i half]-'0');
}
System.out.println(result);

For an input of 123456, prints

[1, 4, 2, 5, 3, 6]

CodePudding user response：

you increment index by 2 and add the char in order so you get alternating characters, the check if(index == s.length()) is to prevent changing of the first element when the string has even characters.

import java.util.*;

public class Main {
    public static void main(String[] args) {
        String s = "123456";    
        int[] result = new int[s.length()];

        int index = 0;
        for (int i = 0; i < s.length(); i  ) {
            result[index%s.length()] = Integer.parseInt(s.charAt(i)   "");
            index  = 2;
            if(index == s.length())
                index  ;
        }
        System.out.println(Arrays.toString(result));
    }
}