计算乘积等于K的所有不同对

// C++ program to count the number of pairs
// whose product is equal to K
#include <algorithm>
#include <iostream>
using namespace std;
#define MAX 100000
// Function to count the number of pairs
// whose product is equal to K
int countPairsWithProductK(int arr[], int n, int k)
{
    // Initialize the count
    int count = 0;
    // Initialize empty hashmap.
    bool hashmap[MAX] = { false };
    // Insert array elements to hashmap
    for (int i = 0; i < n; i++)
        hashmap[arr[i]] = true;
    for (int i = 0; i < n; i++) {
        int x = arr[i];
        double index = 1.0 * k / arr[i];
        // Checking if the index is a whole number
        // and present in the hashmap
        if (index >= 0
            && ((index - (int)(index)) == 0)
            && hashmap[k / x])
            count++;
        hashmap[x] = false;
    }
    return count;
}
// Driver code
int main()
{
    int arr[] = { 1, 5, 3, 4, 2 };
    int N = sizeof(arr) / sizeof(arr[0]);
    int K = 3;
    cout << countPairsWithProductK(arr, N, K);
    return 0;
}


// Java program to count the number of pairs
// whose product is equal to K
class GFG
{
    static int MAX = 100000;
    // Function to count the number of pairs
    // whose product is equal to K
    static int countPairsWithProductK(int arr[], int n, int k)
    {
        // Initialize the count
        int count = 0;
        int i;
        // Initialize empty hashmap.
        boolean hashmap[] = new boolean[MAX];
        // Insert array elements to hashmap
        for (i = 0; i < n; i++)
            hashmap[arr[i]] = true;
        for (i = 0; i < n; i++) {
            int x = arr[i];
            double index = 1.0 * k / arr[i];
            // Checking if the index is a whole number
            // and present in the hashmap
            if (index >= 0
                && ((index - (int)(index)) == 0)
                && hashmap[k / x])
                count++;
            hashmap[x] = false;
        }
        return count;
    }
    // Driver code
    public static void main(String []args)
    {
        int arr[] = { 1, 5, 3, 4, 2 };
        int N = arr.length;
        int K = 3;
        System.out.print(countPairsWithProductK(arr, N, K));
    }
}


# Python3 program to count the number of pairs
# whose product is equal to K
MAX = 100000;
# Function to count the number of pairs
# whose product is equal to K
def countPairsWithProductK(arr, n, k) :
    # Initialize the count
    count = 0;
    # Initialize empty hashmap.
    hashmap = [False]*MAX ;
    # Insert array elements to hashmap
    for i in range(n) :
        hashmap[arr[i]] = True;
    for i in range(n) :
        x = arr[i];
        index = 1.0 * k / arr[i];
        # Checking if the index is a whole number
        # and present in the hashmap
        if (index >= 0
            and ((index - int(index)) == 0)
            and hashmap[k // x]) :
                count += 1;
        hashmap[x] = False;
    return count;
# Driver code
if __name__ == "__main__" :
    arr = [ 1, 5, 3, 4, 2 ];
    N = len(arr);
    K = 3;
    print(countPairsWithProductK(arr, N, K));
# This code is contributed by AnkitRai01


// C# program to count the number of pairs
// whose product is equal to K     
using System;
class GFG
{
    static int MAX = 100000;
    // Function to count the number of pairs
    // whose product is equal to K
    static int countPairsWithProductK(int []arr, int n, int k)
    {
        // Initialize the count
        int count = 0;
        int i;
        // Initialize empty hashmap.
        bool []hashmap = new bool[MAX];
        // Insert array elements to hashmap
        for (i = 0; i < n; i++)
            hashmap[arr[i]] = true;
        for (i = 0; i < n; i++) {
            int x = arr[i];
            double index = 1.0 * k / arr[i];
            // Checking if the index is a whole number
            // and present in the hashmap
            if (index >= 0
                && ((index - (int)(index)) == 0)
                && hashmap[k / x])
                count++;
            hashmap[x] = false;
        }
        return count;
    }
    // Driver code
    public static void Main(String []args)
    {
        int []arr = { 1, 5, 3, 4, 2 };
        int N = arr.Length;
        int K = 3;
        Console.Write(countPairsWithProductK(arr, N, K));         
    }
}
// This code is contributed by 29AjayKumar


<script>
// Javascript program to count the number of pairs
// whose product is equal to K
    let MAX = 100000;
    // Function to count the number of pairs
    // whose product is equal to K
    function countPairsWithProductK(arr,n,k)
    {
        // Initialize the count
        let count = 0;
        let i;
        // Initialize empty hashmap.
        let hashmap = new Array(MAX);
        // Insert array elements to hashmap
        for (i = 0; i < n; i++)
            hashmap[arr[i]] = true;
        for (i = 0; i < n; i++) {
            let x = arr[i];
            let index = 1.0 * k / arr[i];
            // Checking if the index is a whole number
            // and present in the hashmap
            if (index >= 0
                && ((index - Math.floor(index)) == 0)
                && hashmap[k / x])
                count++;
            hashmap[x] = false;
        }
        return count;
    }
    // Driver code
    let arr=[1, 5, 3, 4, 2];
    let N = arr.length;
    let K = 3;
    document.write(countPairsWithProductK(arr, N, K));
// This code is contributed by rag2127
script>


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