Partition negative and positive without comparison with 0

Given an array of n integers, both negative and positive, partition them into two different arrays without comparing any element with 0.

Examples:

Input : arr[] = [1, -2, 6, -7, 8]
Output : a[] = [1, 6, 8] 
         b[] = [-2, -7]

Algorithm:

1. Initialize two empty vectors. Push the first element of the array into any of the two vectors. Suppose the first vector. Let it be denoted by x.
2. For every other element, arr[1] to arr[n-1], check if its sign and the sign of x are the same or not. If the signs are the same, then push the element in the same vector. Else, push the element into the other vector.
3. After the traversal of the two vectors has been completed, print both the vectors. 

How to check if their signs are opposite or not? 
Let the integers be checked to be denoted by x and y. The sign bit is 1 in negative numbers, and 0 in positive numbers. The XOR of x and y will have the sign bit is 1 if and only if they have opposite signs. In other words, the XOR of x and y will be a negative number if and only if x and y have opposite signs.  

Implementation:

CPP

// CPP program to rearrange positive and
// negative numbers without comparison
// with 0.
#include <bits/stdc++.h>
using namespace std;

bool oppositeSigns(int x, int y) { return ((x ^ y) < 0); }

void partitionNegPos(int arr[], int n)
{
    vector<int> a, b;

    // Push first element to a.
    a.push_back(arr[0]);

    // Now put all elements of same sign
    // in a[] and opposite sign in b[]
    for (int i = 1; i < n; i++) {
        if (oppositeSigns(a[0], arr[i]))
            b.push_back(arr[i]);
        else
            a.push_back(arr[i]);
    }

    // Print a[] and b[]
    for (int i = 0; i < a.size(); i++)
        cout << a[i] << ' ';
    cout << '\n';
    for (int i = 0; i < b.size(); i++)
        cout << b[i] << ' ';
}

int main()
{
    int arr[] = { 1, -2, 6, -7, 8 };
    int n = sizeof(arr) / sizeof(arr[0]);
    partitionNegPos(arr, n);
    return 0;
}

Java

// Java program to rearrange positive and
// negative numbers without comparison
// with 0.
import java.util.*;

class GFG {

    static boolean oppositeSigns(int x, int y)
    {
        return ((x ^ y) < 0);
    }

    static void partitionNegPos(int arr[], int n)
    {
        Vector<Integer> a = new Vector<Integer>();
        Vector<Integer> b = new Vector<Integer>();

        // Push first element to a.
        a.add(arr[0]);

        // Now put all elements of same sign
        // in a[] and opposite sign in b[]
        for (int i = 1; i < n; i++) {
            if (oppositeSigns(a.get(0), arr[i]))
                b.add(arr[i]);
            else
                a.add(arr[i]);
        }

        // Print a[] and b[]
        for (int i = 0; i < a.size(); i++)
            System.out.print(a.get(i) + " ");
        System.out.println("");
        for (int i = 0; i < b.size(); i++)
            System.out.print(b.get(i) + " ");
    }

    public static void main(String[] args)
    {
        int arr[] = { 1, -2, 6, -7, 8 };
        int n = arr.length;
        partitionNegPos(arr, n);
    }
}

// This code has been contributed by 29AjayKumar

Python3

# Python3 program to rearrange positive
# and negative numbers without comparison
# with 0.


def oppositeSigns(x, y):

    return ((x ^ y) < 0)


def partitionNegPos(arr, n):

    a = []
    b = []

    # Push first element to a.
    a = a + [arr[0]]

    # Now put all elements of same sign
    # in a[] and opposite sign in b[]
    for i in range(1, n):
        if (oppositeSigns(a[0], arr[i])):
            b = b + [arr[i]]
        else:
            a = a + [arr[i]]

    # Print a[] and b[]
    for i in range(0, len(a)):
        print(a[i], end=' ')
    print("")

    for i in range(0, len(b)):
        print(b[i], end=' ')


# Driver code
arr = [1, -2, 6, -7, 8]
n = len(arr)
partitionNegPos(arr, n)

# This code is contributed by Smitha

C#

// C# program to rearrange positive and
// negative numbers without comparison
// with 0.
using System;
using System.Collections.Generic;

class GFG {

    static bool oppositeSigns(int x, int y)
    {
        return ((x ^ y) < 0);
    }

    static void partitionNegPos(int[] arr, int n)
    {
        List<int> a = new List<int>();
        List<int> b = new List<int>();

        // Push first element to a.
        a.Add(arr[0]);

        // Now put all elements of same sign
        // in a[] and opposite sign in b[]
        for (int i = 1; i < n; i++) {
            if (oppositeSigns(a[0], arr[i]))
                b.Add(arr[i]);
            else
                a.Add(arr[i]);
        }

        // Print a[] and b[]
        for (int i = 0; i < a.Count; i++)
            Console.Write(a[i] + " ");
        Console.WriteLine("");
        for (int i = 0; i < b.Count; i++)
            Console.Write(b[i] + " ");
    }

    // Driver code
    public static void Main()
    {
        int[] arr = { 1, -2, 6, -7, 8 };
        int n = arr.Length;
        partitionNegPos(arr, n);
    }
}

/* This code contributed by PrinciRaj1992 */

Javascript

<script>

// Javascript program to rearrange positive and
// negative numbers without comparison
// with 0.

function oppositeSigns(x, y)
{
    return ((x ^ y) < 0);
}

function partitionNegPos(arr, n)
{
    var a = [], b = [];

    // Push first element to a.
    a.push(arr[0]);

    // Now put all elements of same sign
    // in a[] and opposite sign in b[]
    for (var i = 1; i < n; i++) {
        if (oppositeSigns(a[0], arr[i]))
            b.push(arr[i]);
        else
            a.push(arr[i]);
    }

    // Print a[] and b[]
    for (var i = 0; i < a.length; i++)
        document.write( a[i] + ' ');
    document.write( "<br>" );
    for (var i = 0; i < b.length; i++)
        document.write( b[i] + ' ');
}

var arr = [1, -2, 6, -7, 8];
var n = arr.length;
partitionNegPos(arr, n);


</script>

Output

1 6 8 
-2 -7 

Time Complexity: O(n) 
Auxiliary Space: O(n)

Another approach : Using startswith()

Steps to solve the problem:

1. declare two vector po and ne to store the positive and negative element.

2. iterate through every element of the array as i:

            * declare a string s and store i as string using to_string function.

            * check if last occurrence if “-” in s from 0 is equal to 0 than push i in the ne.

            * else push i in po.

3. iterate through i=0 until end in po:

            * check if i == size of po -1 than print po[i] and break.

            * else just print po[i].

4. iterate through i=0 until end in ne:

            * check if  i == size of ne -1 than print ne[i] and break.

            * else just print ne[i].

Implementation:

C++

// CPP program to rearrange positive and
// negative numbers without comparison
// with 0.
#include <bits/stdc++.h>
using namespace std;

int main()
{
    int arr[] = { 1, -2, 6, -7, 8 };

    vector<int> po, ne;

    // vector<int> ne = new ArrayList<>();

    for (int i : arr) {
        string s = to_string(i);
        if (s.rfind("-", 0) == 0) {
            ne.push_back(i);
        }
        else
            po.push_back(i);
    }

    cout << "[";
    for (int i = 0; i < po.size(); i++) {
        if (i == po.size() - 1) {
            cout << po[i] << "]\n";
            break;
        }
        cout << po[i] << ", ";
    }
    cout << "[";
    for (int i = 0; i < ne.size(); i++) {
        if (i == ne.size() - 1) {
            cout << ne[i] << "]\n";
            break;
        }
        cout << ne[i] << ", ";
    }
}

// This code is contributed by karandeep1234.

Java

/*package whatever //do not write package name here */
import java.util.*;

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

        int[] arr = { 1, -2, 6, -7, 8 };

        List<Integer> po = new ArrayList<>();
        List<Integer> ne = new ArrayList<>();

        for (int i : arr) {
            if ((i + "").startsWith("-")) {
                ne.add(i);
            }
            else
                po.add(i);
        }

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

// This code is contributed by aadityaburujwale.

Python3

# Python3 program to rearrange positive
# and negative numbers without comparison
# with 0.
arr = [1, -2, 6, -7, 8]
x = list(map(str, arr))
po = []
ne = []
for i in x:
    if(i.startswith("-")):
        ne.append(int(i))
    else:
        po.append(int(i))
print(po)
print(ne)

C#

// C# code Addition for the above approach
using System;
using System.Collections;
public class GFG {

    static public void Main()
    {

        // Code
        int[] arr = { 1, -2, 6, -7, 8 };

        var po = new ArrayList();
        var ne = new ArrayList();

        foreach(int i in arr)
        {
            if ((i + "").StartsWith("-")) {
                ne.Add(i);
            }
            else {
                po.Add(i);
            }
        }

        Console.Write("[");
        for (int i = 0; i < po.Count; i++) {
            if (i == po.Count - 1) {
                Console.WriteLine(po[i] + "]");
                break;
            }
            Console.Write(po[i] + ", ");
        }
        Console.Write("[");
        for (int i = 0; i < ne.Count; i++) {
            if (i == ne.Count - 1) {
                Console.WriteLine(ne[i] + "]");
                break;
            }
            Console.Write(ne[i] + ", ");
        }
    }
}

// This code is contributed by lokeshmvs21.

Javascript

let arr = [1, -2, 6, -7, 8 ];

      let po = [];
      let ne = [];

      for(const i of arr){
          if((i+"").startsWith("-")){
            ne.push(i);
        }else po.push(i);
      }

          console.log(JSON.stringify(po));
          console.log(JSON.stringify(ne));

          // This code is contributed by aadityaburujwale.

Output

[1, 6, 8]
[-2, -7]

Time Complexity: O(n) 
Auxiliary Space: O(n)