Create greedy_algo_max_product.cpp

swapnanildutta#9  Submission for Hactoberfest.
Greedy algorithm for Minimum product subset of an array

Algorithms/greedy_algo_max_product.cpp

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+#include <bits/stdc++.h> 
+using namespace std; 
+
+int minProductSubset(int a[], int n) 
+{ 
+	if (n == 1) 
+		return a[0]; 
+
+	// Find count of negative numbers, count of zeros, maximum valued negative number, minimum valued positive number and product of non-zero numbers 
+	int max_neg = INT_MIN; 
+	int min_pos = INT_MAX; 
+	int count_neg = 0, count_zero = 0; 
+	int prod = 1; 
+	for (int i = 0; i < n; i++) { 
+
+		// If number is 0, we don't multiply it with product. 
+		if (a[i] == 0) { 
+			count_zero++; 
+			continue; 
+		} 
+
+		// Count negatives and keep track of maximum valued negative. 
+		if (a[i] < 0) { 
+			count_neg++; 
+			max_neg = max(max_neg, a[i]); 
+		} 
+
+		// Track minimum positive number of array 
+		if (a[i] > 0) 
+			min_pos = min(min_pos, a[i]);		 
+
+		prod = prod * a[i]; 
+	} 
+
+	// If there are all zeros or no negative number present 
+	if (count_zero == n || 
+	(count_neg == 0 && count_zero > 0)) 
+		return 0; 
+
+	// If there are all positive 
+	if (count_neg == 0) 
+		return min_pos; 
+
+	// If there are even number of negative numbers and count_neg not 0 
+	if (!(count_neg & 1) && count_neg != 0) { 
+
+		// Otherwise result is product of all non-zeros divided by maximum valued negative. 
+		prod = prod / max_neg; 
+	} 
+
+	return prod; 
+} 
+
+int main() 
+{ 
+	int a[] = { -1, -5, -2, 7, 3 }; 
+	int n = sizeof(a) / sizeof(a[0]); 
+	cout << minProductSubset(a, n); 
+	return 0; 
+}