Learning course: Java for problem solving - 2
Problem Link: CodeChef: Practical coding for everyone
Feedback
In this problem statement ,the requirement is to make the product of the array’s elements non-negative, which means it should be either 0 or positive. Removing elements from the array is allowed to achieve this goal.
In the given code, if there are any occurrences of zero in the array (count_zero > 0), it implies that the product will be zero regardless of other elements in the array. Therefore, the code correctly prints 0 in this case, as the product is already non-negative and no elements need to be removed.
However, the code incorrectly assumes that having an even count of negative integers (count_neg % 2 == 0) will result in a non-negative product. This assumption is not valid because removing an even number of negative integers can still leave an odd number of negative integers in the array, resulting in a negative product.
To fix this logical error and align with the problem requirements, you should modify the code to print 1 instead of 0 when the count of negative integers is odd (count_neg % 2 == 1). This indicates that it is not possible to make the product non-negative by removing elements from the array.
Here’s the corrected code:
import java.util.*;
class Codechef {
public static void main(String[] args) {
Scanner read = new Scanner(System.in);
int t = read.nextInt();
int ele;
for (int i = 0; i < t; i++) {
int n = read.nextInt();
ArrayList<Integer> a = new ArrayList<Integer>();
for (int j = 0; j < n; j++) {
ele = read.nextInt();
a.add(ele);
}
int count_neg = 0;
int count_zero = Collections.frequency(a, 0);
if (count_zero > 0) {
System.out.println(0);
} else {
int l = 0;
while (l < n) {
if (a.get(l) < 0) {
count_neg = count_neg + 1;
}
l = l + 1;
}
if (count_neg % 2 == 1) {
System.out.println(1); // Print 1 when count_neg is odd
} else {
System.out.println(0);
}
}
}
}
}
With this correction, the code will print 1 when the count of negative integers is odd, indicating that it is not possible to make the product of the array’s elements non-negative by removing elements from the array.