Given an array arr[] consisting of N positive integers, the task is to find the product of the maximum of all possible subsets of the given array. Since the product can be very large, print it to modulo (109 + 7).
Examples:
Input: arr[] = {1, 2, 3}
Output:
Explanation:
All possible subsets of the given array with their respective maximum elements are:
- {1}, the maximum element is 1.
- {2}, the maximum element is 2.
- {3}, the maximum element is 3.
- {1, 2}, the maximum element is 2.
- {1, 3}, the maximum element is 3.
- {2, 3}, the maximum element is 3.
- {1, 2, 3}, the maximum element is 3.
The product of all the above maximum element is 1*2*3*2*3*3*3 = 324.
Input: arr[] = {1, 1, 1, 1}
Output: 1
Naive Approach: The simplest approach to solve the given problem is to generate all possible subsets of the given array and find the product of the maximum of all the generated subsets modulo (109 + 7) as the resultant product.
C++
// C++ code for the approachÂ
#include <bits/stdc++.h>using namespace std;Â
#define mod 1000000007Â
// Function to find the product of the maximum of all// possible subsetslong long int maxProduct(int arr[], int n) {Â Â Â Â long long int ans = 1;Â
    // Generate all possible subsets of the array    for (int i = 0; i < (1 << n); i++) {        long long int maxVal = INT_MIN;Â
        // Find the maximum value of each subset        for (int j = 0; j < n; j++) {            if ((i & (1 << j)) != 0) {                maxVal = max(maxVal, (long long int)arr[j]);            }        }Â
        // Multiply the maximum value of each subset to the        // answer        if (maxVal != INT_MIN)            ans = (ans * maxVal) % mod;    }Â
    return ans;}Â
// Function to print the product of the maximum of all// possible subsets of the arrayvoid printMaxProduct(int arr[], int n) {Â Â Â Â long long int ans = maxProduct(arr, n);Â Â Â Â cout << ans << endl;}Â
// Driver codeint main() {    // Input array    int arr[] = { 1, 2, 3 };    // Size of the array    int n = sizeof(arr) / sizeof(arr[0]);Â
    // Print the product of the maximum of all    // possible subsets of the array    printMaxProduct(arr, n);Â
    return 0;} |
Java
// Java program for the above approachimport java.util.*;Â
public class Main {Â Â Â Â static final int mod = 1000000007;Â
    // Function to find the product of    // the maximum of all possible subsets    static long maxProduct(int[] arr, int n)    {        long ans = 1;Â
        // Generate all possible subsets        // of the array        for (int i = 0; i < (1 << n); i++) {            long maxVal = Integer.MIN_VALUE;Â
            // Find the maximum value of            // each subset            for (int j = 0; j < n; j++) {                if ((i & (1 << j)) != 0) {                    maxVal = Math.max(maxVal, arr[j]);                }            }Â
            // Multiply the maximum value of            // each subset to the answer            if (maxVal != Integer.MIN_VALUE) {                ans = (ans * maxVal) % mod;            }        }Â
        return ans;    }Â
    // Function to print the product of the    // maximum of all possible subsets    // of the array    static void printMaxProduct(int[] arr, int n)    {        long ans = maxProduct(arr, n);        System.out.println(ans);    }Â
    // Driver code    public static void main(String[] args)    {        // Input array        int[] arr = { 1, 2, 3 };        // Size of the array        int n = arr.length;Â
        // Print the product of the maximum of all        // possible subsets of the array        printMaxProduct(arr, n);    }} |
Python3
# Python3 code for the approachMOD = int(1e9 + 7)Â
# Function to find the product of the maximum of all# possible subsetsdef maxProduct(arr, n):  ans = 1     # Generate all possible subsets of the array  for i in range(1 << n):    maxVal = float('-inf')         # Find the maximum value of each subset    for j in range(n):      if i & (1 << j):        maxVal = max(maxVal, arr[j])            # Multiply the maximum value of each subset to the    # answer    if maxVal != float('-inf'):      ans = (ans * maxVal) % MOD                        return ansÂ
# Function to print the product of the maximum of all# possible subsets of the arraydef printMaxProduct(arr, n):    ans = maxProduct(arr, n)    print(ans)   # Driver codeif __name__ == '__main__':    # Input array    arr = [1, 2, 3]    # Size of the array    n = len(arr)         # Print the product of the maximum of all    # possible subsets of the array    printMaxProduct(arr, n) |
C#
using System;Â
public class GFG {Â Â static readonly int mod = 1000000007;Â
  // Function to find the product of  // the maximum of all possible subsets  static long MaxProduct(int[] arr, int n)  {    long ans = 1;Â
    // Generate all possible subsets    // of the array    for (int i = 0; i < (1 << n); i++) {      long maxVal = int.MinValue;Â
      // Find the maximum value of      // each subset      for (int j = 0; j < n; j++) {        if ((i & (1 << j)) != 0) {          maxVal = Math.Max(maxVal, arr[j]);        }      }Â
      // Multiply the maximum value of      // each subset to the answer      if (maxVal != int.MinValue) {        ans = (ans * maxVal) % mod;      }    }Â
    return ans;  }Â
  // Function to print the product of the  // maximum of all possible subsets  // of the array  static void PrintMaxProduct(int[] arr, int n)  {    long ans = MaxProduct(arr, n);    Console.WriteLine(ans);  }Â
  // Driver code  public static void Main()  {    // Input array    int[] arr = { 1, 2, 3 };    // Size of the array    int n = arr.Length;Â
    // Print the product of the maximum of all    // possible subsets of the array    PrintMaxProduct(arr, n);  }}Â
//This code is contributed by aeroabrar_31 |
Javascript
// JavaScript code to find the product of the maximum of all possible subsetsÂ
const mod = 1000000007;Â
function maxProduct(arr, n) {Â Â Â Â let ans = 1;Â
    // Generate all possible subsets of the array    for (let i = 0; i < (1 << n); i++) {        let maxVal = Number.MIN_SAFE_INTEGER;Â
        // Find the maximum value of each subset        for (let j = 0; j < n; j++) {            if ((i & (1 << j)) !== 0) {                maxVal = Math.max(maxVal, arr[j]);            }        }Â
        // Multiply the maximum value of each subset to the answer        if (maxVal !== Number.MIN_SAFE_INTEGER) {            ans = (ans * maxVal) % mod;        }    }Â
    return ans;}Â
function printMaxProduct(arr, n) {Â Â Â Â let ans = maxProduct(arr, n);Â Â Â Â console.log(ans);}Â
// Driver codelet arr = [1, 2, 3];let n = arr.length;Â
// Print the product of the maximum of all possible subsets of the arrayprintMaxProduct(arr, n); |
324
Time Complexity: O(N*2N)
Auxiliary Space: O(1)
Efficient Approach: The above approach can also be optimized based on the following observations:
- The idea is to count the number of times each array element occurs as the maximum element among all possible subsets formed.
- An array element arr[i] is a maximum if and only if all the elements except arr[i] are smaller than or equal to it.
- Therefore, the number of subsets formed by all elements smaller than or equal to each array element arr[i] contributes to the count of subsets having arr[i] as the maximum element.
Follow the steps below to solve the problem:
- Initialize a variable, say maximumProduct as 1 that stores the resultant product of maximum elements of all subsets.
- Sort the given array arr[] in the increasing order.
- Traverse the array from the end using the variable i and perform the following steps:
- Find the number of subsets that are smaller than the current element arr[i] as (2i – 1) and store it in a variable say P.
- Since the array element arr[i] contributes P number of times, therefore multiply the value arr[i], P times to the variable maximumProduct.
- Find the product of the array element with maximumProduct for including all the subsets of size 1.
- After completing the above steps, print the value of maximumProduct as the resultant maximum product.
Below is the implementation of the above approach:
C++
// C++ program for the above approachÂ
#include <bits/stdc++.h>using namespace std;Â
// Function to find the product of the// maximum of all possible subsetslong maximumProduct(int arr[], int N){Â Â Â Â long mod = 1000000007;Â
    // Sort the given array arr[]    sort(arr, arr + N);Â
    // Stores the power of 2    long power[N + 1];    power[0] = 1;Â
    // Calculate the power of 2    for (int i = 1; i <= N; i++) {        power[i] = 2 * power[i - 1];        power[i] %= mod;    }Â
    // Stores the resultant product    long result = 1;Â
    // Traverse the array from the back    for (int i = N - 1; i > 0; i--) {Â
        // Find the value of 2^i - 1        long value = (power[i] - 1);Â
        // Iterate value number of times        for (int j = 0; j < value; j++) {Â
            // Multiply value with            // the result            result *= 1LL * arr[i];            result %= mod;        }    }Â
    // Calculate the product of array    // elements with result to consider    // the subset of size 1    for (int i = 0; i < N; i++) {        result *= 1LL * arr[i];        result %= mod;    }Â
    // Return the resultant product    return result;}Â
// Driver Codeint main(){Â
    int arr[] = { 1, 2, 3 };    int N = sizeof(arr) / sizeof(arr[0]);    cout << maximumProduct(arr, N);Â
    return 0;} |
Java
// Java program for the above approachimport java.util.Arrays;Â
class GFG{Â
// Function to find the product of the// maximum of all possible subsetsstatic long maximumProduct(int arr[], int N){Â Â Â Â long mod = 1000000007;Â
    // Sort the given array arr[]    Arrays.sort(arr);Â
    // Stores the power of 2    long power[] = new long[N + 1];    power[0] = 1;Â
    // Calculate the power of 2    for(int i = 1; i <= N; i++)     {        power[i] = 2 * power[i - 1];        power[i] %= mod;    }Â
    // Stores the resultant product    long result = 1;Â
    // Traverse the array from the back    for(int i = N - 1; i > 0; i--)     {                 // Find the value of 2^i - 1        long value = (power[i] - 1);Â
        // Iterate value number of times        for(int j = 0; j < value; j++)         {                         // Multiply value with            // the result            result *= arr[i];            result %= mod;        }    }Â
    // Calculate the product of array    // elements with result to consider    // the subset of size 1    for(int i = 0; i < N; i++)    {        result *= arr[i];        result %= mod;    }Â
    // Return the resultant product    return result;}Â
// Driver Codepublic static void main(String[] args){Â Â Â Â int arr[] = { 1, 2, 3 };Â Â Â Â int N = arr.length;Â Â Â Â Â Â Â Â Â System.out.println(maximumProduct(arr, N));}}Â
// This code is contributed by rishavmahato348 |
Python3
# Python3 program for the above approachÂ
# Function to find the product of the# maximum of all possible subsetsdef maximumProduct(arr, N):Â Â Â Â Â Â Â Â Â mod = 1000000007Â
    # Sort the given array arr[]    arr = sorted(arr)Â
    # Stores the power of 2    power = [0] * (N + 1)    power[0] = 1Â
    # Calculate the power of 2    for i in range(1, N + 1):        power[i] = 2 * power[i - 1]        power[i] %= modÂ
    # Stores the resultant product    result = 1Â
    # Traverse the array from the back    for i in range(N - 1, -1, -1):                 # Find the value of 2^i - 1        value = (power[i] - 1)Â
        # Iterate value number of times        for j in range(value):                         # Multiply value with            # the result            result *= arr[i]            result %= modÂ
    # Calculate the product of array    # elements with result to consider    # the subset of size 1    for i in range(N):        result *= arr[i]        result %= mod             # Return the resultant product    return resultÂ
# Driver Codeif __name__ == '__main__':Â Â Â Â Â Â Â Â Â arr = [ 1, 2, 3 ]Â Â Â Â N = len(arr)Â Â Â Â Â Â Â Â Â print(maximumProduct(arr, N))Â
# This code is contributed by mohit kumar 29 |
C#
// C# program for the above approachusing System;using System.Collections.Generic;Â
class GFG{Â
// Function to find the product of the// maximum of all possible subsetsstatic long maximumProduct(int []arr, int N){Â Â Â Â long mod = 1000000007;Â
    // Sort the given array arr[]    Array.Sort(arr);Â
    // Stores the power of 2    long []power = new long[N + 1];    power[0] = 1;Â
    // Calculate the power of 2    for (int i = 1; i <= N; i++) {        power[i] = 2 * power[i - 1];        power[i] %= mod;    }Â
    // Stores the resultant product    long result = 1;Â
    // Traverse the array from the back    for (int i = N - 1; i > 0; i--) {Â
        // Find the value of 2^i - 1        long value = (power[i] - 1);Â
        // Iterate value number of times        for (int j = 0; j < value; j++) {Â
            // Multiply value with            // the result            result *= 1 * arr[i];            result %= mod;        }    }Â
    // Calculate the product of array    // elements with result to consider    // the subset of size 1    for (int i = 0; i < N; i++) {        result *= 1 * arr[i];        result %= mod;    }Â
    // Return the resultant product    return result;}Â
// Driver Codepublic static void Main(){Â
    int []arr = {1, 2, 3};    int N = arr.Length;    Console.Write(maximumProduct(arr, N));}}Â
// This code is contributed by SURENDRA_GANGWAR. |
Javascript
<script>Â
// JavaScript program for the above approachÂ
Â
// Function to find the product of the// maximum of all possible subsetsfunction maximumProduct(arr, N){Â Â Â Â let mod = 1000000007;Â
    // Sort the given array arr[]    arr.sort((a, b) => a - b);Â
    // Stores the power of 2    let power = new Array(N + 1);    power[0] = 1;Â
    // Calculate the power of 2    for (let i = 1; i <= N; i++) {        power[i] = 2 * power[i - 1];        power[i] %= mod;    }Â
    // Stores the resultant product    let result = 1;Â
    // Traverse the array from the back    for (let i = N - 1; i > 0; i--) {Â
        // Find the value of 2^i - 1        let value = (power[i] - 1);Â
        // Iterate value number of times        for (let j = 0; j < value; j++) {Â
            // Multiply value with            // the result            result *= 1 * arr[i];            result %= mod;        }    }Â
    // Calculate the product of array    // elements with result to consider    // the subset of size 1    for (let i = 0; i < N; i++) {        result *= 1 * arr[i];        result %= mod;    }Â
    // Return the resultant product    return result;}Â
// Driver CodeÂ
let arr = [1, 2, 3 ];let N = arr.length;document.write(maximumProduct(arr, N));Â
</script> |
324
Â
Time Complexity: O(N*)
Auxiliary Space: O(N)
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!

… [Trackback]
[…] Find More Information here to that Topic: geeksforgeeks.org/product-of-the-maximums-of-all-subsets-of-an-array/ […]
… [Trackback]
[…] Find More Information here on that Topic: geeksforgeeks.org/product-of-the-maximums-of-all-subsets-of-an-array/ […]