3 numbers in ascending order WITHOUT the use of conditional statements in Java. As in I can't use if statements at all

Question

My code looks like this so far:

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

        int num1 = Integer.parseInt(args[0]);
        int num2 = Integer.parseInt(args[1]);
        int num3 = Integer.parseInt(args[2]);


        int x = Math.min(num1, num2);
        int min = Math.min(x,num3);
        int z = Math.max(num1, num2);
        int max = Math.max(z, num3);

        int a = 0;
        int mid = 0;



        while (mid >= min && mid <= max) {

        mid = a;

        }

        System.out.println(min);
        System.out.println(a);
        System.out.println(max);



    }

I know how to do the min and the max but I'm having troubles with the middle one. Any idea how to do that without conditional statements?

Is it cheating to write `mid = num1 + num2 + num3 - min - max;` after you've worked out `min` and `max`? — Dawood ibn Kareem, Jan 19 '15 at 23:23
Seems more suited to [Programming Puzzles & Code Golf](http://codegolf.stackexchange.com/). — David Conrad, Jan 19 '15 at 23:24
This seems perfect actually! I do just need to do them for 3 numbers and this is such a simple way. Thanks :) — msd, Jan 20 '15 at 06:06
There are just too many ways to do this without further constrains like no list allowed etc. — zubergu, Jan 27 '15 at 09:28

score 6 · Answer 1 · edited May 23 '17 at 12:08

in this case there is a simple algorithm for it:

mid = Math.max(Math.min(num1,num2), Math.min(Math.max(num1,num2),num3));

Also as the operator ^ denotes bitwise xor. so another way is:

mid=num1^num2^num3^max^min;

EXAMPLE:

public static void main(String[] args) {
    System.out.println(mid(70, 3, 10));
}

static int mid(int a, int b, int c) {
    int mx = Math.max(Math.max(a, b), c);
    int mn = Math.min(Math.min(a, b), c);
    int md = a ^ b ^ c ^ mx ^ mn;
    return md;
}

OUTPUT: 10.

Also as OldCurmudgeon said below you can calculate the mid with below formula:

int mid = num1 + num2 + num3 - min - max;

Wow. Now all you need is to replace each `Math.max(x,y)` with `(((x-y)&Integer.MIN_VALUE)>>31)*(y-x)+x` and you're sorted! — Dawood ibn Kareem, Jan 19 '15 at 23:55

score 3 · Answer 2 · answered Jan 19 '15 at 23:15

3

Put them in a List and sort it...

List<Integer> ints = new LinkedList<>();
ints.add(Integer.parseInt(args[0]));
ints.add(Integer.parseInt(args[1]));
ints.add(Integer.parseInt(args[2]));

Collections.sort(ints); // smallest -> greatest
System.out.println(ints);

Collections.reverse(ints); // greatest -> smallest
System.out.println(ints);

answered Jan 19 '15 at 23:15

Todd

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That uses conditionals under the hood. – Engineer Dec 20 '20 at 07:58

OldCurmudgeon · Answer 3 · 2015-01-21T23:48:36.570

3

int mid = num1 + num2 + num3 - min - max;

Sorry for briefness - posted from my phone.

It must be self-evident that the middle number is the sum of the three numbers minus the max minus the min. Would also work if max == mid or max == min or even both.

edited Jan 21 '15 at 23:48

answered Jan 20 '15 at 00:13

OldCurmudgeon

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a really wisely answer, I'll mention this answer in my answer if you are not agree just tell me to remove the mentioning. +1 – void Jan 21 '15 at 23:40
@FarhangAmary - I'd be pleased with a mention. :) – OldCurmudgeon Jan 21 '15 at 23:46

score 0 · Answer 4 · answered Jan 19 '15 at 23:57

Assuming this is some kind of puzzle/homework are you allowed to use the ternary operator?

int[] ints = {3, 1, 2};
int min = ints[0] <= ints[1] && ints[0] <= ints[2]
          ? ints[0]
          : ints[1] <= ints[0] && ints[1] <= ints[2]
            ? ints[1]
            : ints[2];

probinso · Answer 5 · 2016-07-08T19:55:43.400

This is how I would implement three_sort without any if statements or ternary operators. You would have to adapt this to your language of choice.

def two_sort(a, b):
    small = int(a < b)  * a + int(a >= b) * b
    large = int(a >= b) * a + int(a < b)  * b
    return small, large

def three_sort(a, b, c):
    a, b = two_sort(a, b)
    a, c = two_sort(a, c)
    b, c = two_sort(b, c)
    return a, b, c

for a more general solution:

from random    import randint

def two_sort(a, b):
    small = int(a < b)  * a + int(a >= b) * b
    large = int(a >= b) * a + int(a < b)  * b
    return small, large

    return li[-1]

def n_sort(li):
    for _ in li:
        for i, _ in enumerate(li[:-1]):
            li[i], li[i+1] = two_sort(li[i], li[i+1])
    return li

N = 10
li = [randint(0, 1000) for _ in range(N)]
print(N_Sort(N)(*li))

score 0 · Answer 6 · answered Jun 19 '17 at 18:59

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

        // command-line input
        int a = Integer.parseInt(args[0]);
        int b= Integer.parseInt(args[1]);
        int c = Integer.parseInt(args[2]);


        // compute the order

        int max=Math.max(Math.max(a,b),c);
        int min =Math.min(Math.min(a,b ), c);
        int middle = a + b + c - max - min;


        // output in ascending order

        System.out.println(min+"\n" + middle+ "\n"+ max);

    }
}

3 numbers in ascending order WITHOUT the use of conditional statements in Java. As in I can't use if statements at all

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