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Maximum of four numbers without using conditional or bitwise operator
  • Difficulty Level : Medium
  • Last Updated : 03 Feb, 2020

Given four numbers, print the maximum of the 4 entered numbers without using conditional or bitwise operator (not even ternary operators).

Examples:

Input : 4 8 6 5
Output : 8

Input : 11 17 8 17
Output : 17

We use the fact that value of “(x – y + abs(x – y))” will be 0 of x is less than or equal to y. We use this value as index in an array of size 2 to pick maximum. Once we have found maximum of two elements, we can use same technique for finding maximum of all.

C++




// CPP program to find maximum of 4 numbers
// without using conditional and bitwise
// operators.
#include <bits/stdc++.h>
using namespace std;
  
int maxOfFour(int w, int x, int y, int z)
{
    int a[2];
    a[0] = w, a[1] = x;
  
    // b is 0 if w is less than or equal
    // to x, else it is non-zero.
    bool b = (a[0] - a[1] + abs(a[0] - a[1]));
  
    // After below operation, a[0] is maximum
    // of w and x.
    swap(a[0], a[!b]);
  
    // After below three steps, a[0] is maximum
    // of w, x and y.
    a[1] = y;
    b = (a[0] - a[1] + abs(a[0] - a[1]));
    swap(a[0], a[!b]);
  
    // After below three steps, a[0] is maximum
    // of w, x, y and z.
    a[1] = z;
    b = (a[0] - a[1] + abs(a[0] - a[1]));
    swap(a[0], a[!b]);
  
    return a[0];
}
  
// Driver code
int main()
{
    int w = 12, x = 15, y = 18, z = 17;
    cout << "Maximum of four : "
         << maxOfFour(w, x, y, z);
    return 0;
}

Python




# Python program to find maximum of 4 numbers 
# without using conditional and bitwise 
# operators. 
def maxOfFour(w, x, y, z):
    a = [0] * 2
    a[0] = w
    a[1] =
      
    # b is 0 if w is less than or equal 
    # to x, else it is non-zero. 
    b = bool(a[0] - a[1] + abs(a[0] - a[1]))
    if b: 
        b = 1
    else
        b = 0
  
    # After below operation, a[0] is maximum 
    # of w and x. 
    a[0], a[1 - b] = a[1 - b], a[0]
      
    # After below three steps, a[0] is maximum 
    # of w, x and y. 
    a[1] =
    b = bool(a[0] - a[1] + abs(a[0] - a[1])) 
    if b: 
        b = 1
    else
        b = 0
    a[0], a[1 - b] = a[1 - b], a[0]
      
    # After below three steps, a[0] is maximum 
    # of w, x, y and z. 
    a[1] =
    b = bool(a[0] - a[1] + abs(a[0] - a[1]))
    if b: 
        b = 1
    else
        b = 0
    a[0], a[1 - b] = a[1 - b], a[0]
      
    return a[0
  
# Driver code 
w = 12
x = 15
y = 18
z = 17
print("Maximum of four : ", maxOfFour(w, x, y, z))
  
# This code is contributed by SHUBHAMSINGH10


Output:



Maximum of four : 18

This article is contributed by Arkajyoti Banerjee. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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