Random list of M non-negative integers whose sum is N

Given two integers M and N, the task is to create a list of M non-negative integers whose sum is N. In case when more than one list is possible, find any one.

Examples:

Input: M = 4, N = 8
Output: 1 3 3 1
1 + 3 + 3 + 1 = 8



Input: M = 5, N = 3
Output: 0 1 1 0 1

Approach: To get a complete random list of integers, create an array of size M where every element is initialised with 0. Now run a loop from 0 to N – 1 and increment any randomly chosen element from the array by 1 using the rand() function. This way, sum of the resuntant list will be N.

Below is the implementation of the above approach:

C++

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// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
  
// Utility function to print the
// elements of an array
void printArr(int arr[], int n)
{
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
}
  
// Function to generate a list of
// m random non-negative integers
// whose sum is n
void randomList(int m, int n)
{
  
    // Create an array of size m where
    // every element is initialized to 0
    int arr[m] = { 0 };
    srand(time(0));
  
    // To make the sum of the final list as n
    for (int i = 0; i < n; i++) {
  
        // Increment any random element
        // from the array by 1
        arr[rand() % m]++;
    }
  
    // Print the generated list
    printArr(arr, m);
}
  
// Driver code
int main()
{
    int m = 4, n = 8;
  
    randomList(m, n);
  
    return 0;
}

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Java

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// Java implementation of the approach
class GFG
{
      
// Utility function to print the
// elements of an array
static void printArr(int arr[], int n)
{
    for (int i = 0; i < n; i++)
        System.out.print(arr[i] + " ");
}
  
// Function to generate a list of
// m random non-negative integers
// whose sum is n
static void randomList(int m, int n)
{
  
    // Create an array of size m where
    // every element is initialized to 0
    int arr[] = new int[m];
      
    // To make the sum of the final list as n
    for (int i = 0; i < n; i++)
    {
  
        // Increment any random element
        // from the array by 1
        arr[(int)(Math.random() * m)]++;
    }
  
    // Print the generated list
    printArr(arr, m);
}
  
// Driver code
public static void main(String args[])
{
    int m = 4, n = 8;
  
    randomList(m, n);
}
}
  
// This code is contributed by Arnab Kundu

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Python3

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# Python3 implementation of the approach 
from random import randint
  
# Utility function to print the 
# elements of an array 
def printArr(arr, n) :
  
    for i in range(n) :
        print(arr[i], end = " "); 
  
# Function to generate a list of 
# m random non-negative integers 
# whose sum is n 
def randomList(m, n): 
  
    # Create an array of size m where 
    # every element is initialized to 0 
    arr = [0] * m; 
      
    # To make the sum of the final list as n 
    for i in range(n) :
  
        # Increment any random element 
        # from the array by 1 
        arr[randint(0, n) % m] += 1
  
    # Print the generated list 
    printArr(arr, m); 
  
# Driver code 
if __name__ == "__main__"
  
    m = 4; n = 8
  
    randomList(m, n); 
  
# This code is contributed by AnkitRai01

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C#

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// C# implementation of the approach
using System;
  
class GFG
{
      
// Utility function to print the
// elements of an array
static void printArr(int []arr, int n)
{
    for (int i = 0; i < n; i++)
        Console.Write(arr[i] + " ");
}
  
// Function to generate a list of
// m random non-negative integers
// whose sum is n
static void randomList(int m, int n)
{
  
    // Create an array of size m where
    // every element is initialized to 0
    int [] arr = new int[m];
      
    // To make the sum of the final list as n
    for (int i = 0; i < n; i++)
    {
  
        // Increment any random element
        // from the array by 1
        Random rnd = new Random();
  
        arr[rnd.Next(0, n) % m]++;
    }
  
    // Print the generated list
    printArr(arr, m);
}
  
// Driver code
public static void Main()
{
    int m = 4, n = 8;
  
    randomList(m, n);
}
}
  
// This code is contributed by Mohit kumar

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Output:

1 3 3 1

Time Complexity: O(max(M, N))



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