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An artificial neuron multiplies each input by a weight, adds a bias, and passes the result through an activation function:
z = x₁×w₁ + x₂×w₂ + … + xₙ×wₙ + bias
output = sigmoid(z) = 1 / (1 + e^(-z))
Implement neuron_output(inputs, weights, bias).
Input
inputs: The input values.
weights: One weight per input (same length as inputs).
bias: The neuron's bias.
Output
Return the neuron's output, a decimal number between 0 and 1.
Constraints
1 ≤ length of inputs = length of weights ≤ 100
-10 ≤ each input, weight and bias ≤ 10
Examples
Example 1
Input:
inputs = [1.0, 2.0, 3.0]
weights = [0.2, 0.4, 0.6]
bias = 0.5
Expected output:
0.964429Explanation
z = 1×0.2 + 2×0.4 + 3×0.6 + 0.5 = 3.3, and sigmoid(3.3) ≈ 0.964429.
Example 2
Input:
inputs = [0.5, -1.0]
weights = [2.0, 1.0]
bias = 0.0
Expected output:
0.5Explanation
z = 0.5×2 + (-1)×1 + 0 = 0, and sigmoid(0) = 0.5: the neuron is exactly undecided.
References
-
Example 1 Not runInput:
inputs = [1.0, 2.0, 3.0] weights = [0.2, 0.4, 0.6] bias = 0.5Expected output:0.964429Your output -
Example 2 Not runInput:
inputs = [0.5, -1.0] weights = [2.0, 1.0] bias = 0.0Expected output:0.5Your output
4 hidden tests also run when you submit. If your code fails one, you'll see that test. Solve the challenge to see them all.
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💡 Java Basics & Examples You Can Try Above
1. Declaring Variables and Constants
Java requires you to declare the type of each variable. Use final for constants.
int age = 30;
double pi = 3.14159;
char grade = 'A';
String name = "Alice";
boolean isActive = true;
// Constants
final int MAX_USERS = 100;
final String COMPANY = "CodeUtility";2. Conditionals (if / switch)
Use if, else if, and switch for control flow.
int x = 2;
if (x == 1) {
System.out.println("One");
} else if (x == 2) {
System.out.println("Two");
} else {
System.out.println("Other");
}
switch (x) {
case 1:
System.out.println("One");
break;
case 2:
System.out.println("Two");
break;
default:
System.out.println("Other");
}3. Loops
Use for, while, and do-while for iteration.
for (int i = 0; i < 3; i++) {
System.out.println(i);
}
int n = 3;
while (n > 0) {
System.out.println(n);
n--;
}4. Arrays
Arrays hold fixed-size sequences of the same type.
int[] numbers = {10, 20, 30};
System.out.println(numbers[1]);5. ArrayList Manipulation
Use ArrayList for dynamic-sized lists.
import java.util.ArrayList;
ArrayList<Integer> nums = new ArrayList<>();
nums.add(1);
nums.add(2);
nums.add(3);
nums.remove(Integer.valueOf(2));
for (int num : nums) {
System.out.print(num + " ");
}6. Console Input/Output
Use Scanner for input and System.out for output.
import java.util.Scanner;
Scanner scanner = new Scanner(System.in);
System.out.print("Enter your name: ");
String name = scanner.nextLine();
System.out.println("Hello, " + name);7. Functions
Define methods with return types and parameters.
public static int add(int a, int b) {
return a + b;
}
System.out.println(add(3, 4));8. HashMaps
Use HashMap for key-value storage.
import java.util.HashMap;
HashMap<String, Integer> ages = new HashMap<>();
ages.put("Alice", 30);
System.out.println(ages.get("Alice"));9. Exception Handling
Use try and catch to handle runtime exceptions.
try {
throw new Exception("Something went wrong");
} catch (Exception e) {
System.out.println(e.getMessage());
}10. File I/O
Use Files and Paths from java.nio.file for file handling.
import java.nio.file.*;
import java.io.IOException;
Files.writeString(Paths.get("file.txt"), "Hello File");
String content = Files.readString(Paths.get("file.txt"));
System.out.println(content);11. String Manipulation
Java strings support many methods like length(), substring(), and contains().
String text = "Hello World";
System.out.println(text.length());
System.out.println(text.substring(0, 5));
System.out.println(text.contains("World"));12. Classes & Objects
Java supports object-oriented programming using classes and instances.
class Person {
String name;
Person(String name) {
this.name = name;
}
void greet() {
System.out.println("Hi, I'm " + name);
}
}
Person p = new Person("Alice");
p.greet();