Creating a discoverLargest() function, with functionalities akin to Math.max()

Assigned with the task of creating a function that loops through an array of any size and returns the largest value, I faced some challenges.

Simple, right? Not so much when limited to using only for loops and no Math functions. Although I knew about Math.max(), I had to come up with an alternative solution which required some careful thinking.

It took me around two hours, including 30 minutes of slow debugging, but I believe I finally cracked it. Here's what I came up with:

function findMax(myArray) {
    var maxNumber;
    aLength = myArray.length;
for(var i = 0; i < aLength - 1; i++){
    
    var currentNumber = myArray[i];
    var nextNumber = myArray[i + 1];
    if(maxNumber > currentNumber){
         maxNumber = maxNumber}

    else if(currentNumber > nextNumber){
         maxNumber = currentNumber;

    } else if (nextNumber > currentNumber){
         maxNumber = nextNumber;
    }

} return maxNumber;

This solution worked perfectly, but I felt it could be optimized for better performance.

Some might question why I declared a variable for the array length instead of directly using myArray.length. The reason is that Google Chrome's Web Dev Tool regularly gave me incorrect results, failing to read the length property within the for loop condition statement.

How would you have approached writing this code?

Answer №1

Check out this handy tip:

function findMax(arr) {
  let max = arr[0] || -Infinity;
  for (let i of arr)
    max = max > i ? max : i;
  return max;
}

If you're unable to utilize Math.max() solely because you are dealing with an array, you can try the following alternatives:

Math.max.apply(null, array);

or

Math.max(...array);  // utilizing the spread operator in ECMA-script

Answer №2

The function you have created is currently not functioning as intended. For instance, when provided with the input [1, 200, 3, 400], it incorrectly outputs 200 instead of 400.

This task challenges you to devise an algorithm for identifying the maximum value in an array without utilizing built-in Math functions.

When faced with such a challenge, approaching it logically and sequentially is crucial. Attempt to tackle the problem using a human thought process, breaking down the logic into manageable steps. Consider the following steps while iterating through the array:

  1. Determine if the current number is greater than the current maximum number.
  2. If so, update the maximum number to this new value.
  3. If not, proceed to the next number without making any changes.
  4. Continue this process until all numbers in the array have been evaluated.

This framework outlines how your algorithm should operate. However, certain complications may arise. For example, what should be considered the initial current maximum number when analyzing the first array element? To address this issue, set the initial current maximum number to the first array element before commencing the algorithm. Subsequently, identify any numbers larger than this initial maximum and adjust accordingly.

A revised version of your findMax() function could take this form (refer to code comments for additional insights):

function findMax(myArray) {
  var maxNumber = myArray[0]; // Initialize maxNumber to first array element 
  
  for (var i = 1; i < myArray.length; i++) { 
    var currentNumber = myArray[i]; 
    
    if(currentNumber > maxNumber) { 
      maxNumber = currentNumber;
    }
  }
  
  return maxNumber;
}

console.log(findMax([1, 200, , 3, 400])); // Output: 400

In pursuit of mimicking Math.max() functionality meticulously, refer to this resource illustrating Chrome V8's method implementation.

The presented approach represents just one strategy for navigating the complex realm of finding the highest value within an array.

For those concerned with performance, bear in mind that succinct code does not always equate to optimal efficiency.

The outlined solution exhibits a time complexity of O(N), denoting evaluation of each element in the array to determine the highest value. Although computations may lengthen with growing arrays, the fundamental principle remains – scrutinizing every element is indispensable towards pinpointing the maximal value.

Exploring alternative data structures like a max-heap could prove advantageous, furnishing improved time complexity and performance metrics. The utilization of a 'max-heap' permits instantaneous retrieval of the maximum value (O(1)) from the data structure, streamlining processes significantly. While not mandatory for implementation, awareness of these advanced concepts can enhance problem-solving capabilities.

Answer №3

Another approach is to utilize the reduce method.

Here is a sample implementation:

const findMaxNumber = (nums) => nums.reduce((prev, current) => {
 return current > prev ? current : prev;
})

console.log(findMaxNumber([2,7,9])) // 9

const findMaxNumber = (nums) => nums.reduce((prev, current) => {
 return current > prev ? current : prev;
})

console.log(findMaxNumber([3,12,15]))

Answer №4

Using three if-else statements below may not be the most efficient approach since the for loop already iterates through the array length;

function findLargestNumber(myArray = []) {
    let arrayLength = myArray.length;
    if (arrayLength === 0) return;

    let maxNum = myArray[0];
    for (let i = 0; i < arrayLength; i++) {
        if (myArray[i] > maxNum) {
            maxNum = myArray[i];
        }
    } 
    return maxNum;
}

console.log(findLargestNumber([4, 2, 3, 78, 0, 9]));

Answer №5

It's important not to overthink the problem of finding the maximum value in an array. The process involves comparing each element with the current maximum value and updating it if a larger value is found. This ensures that the final result is indeed the largest value in the array.

In the code snippet below, I begin by setting the max value to null. If the array is empty, the function simply returns null. This is a personal convention and can be adjusted based on specific requirements.

Assuming the array has at least one element, the max value is initialized with the first element. Subsequently, each element from index 1 to n-1 is compared with the current max value and updated accordingly.

It's worth noting that some implementations use Number.MIN_VALUE as the initial max value. However, this approach may fail if the array contains Number.MIN_VALUE itself.

function findMax(myArray) {
  let len = myArray.length;
  let max = null;
  
  if (len === 0)
    return max;
    
  max = myArray[0];
  
  for (var i = 1; i < len; i++) {
    if (myArray[i] > max)
      max = myArray[i];
  }
  
  return max;
}

let arr = [1, 3, 4, -2, -4, 8, 16, 0, -18, 6];
let empty = [];

console.log(findMax(arr));
console.log(findMax(empty));

Bonus: An alternative method using reduce() function in JavaScript which operates similarly but in a more elegant and concise manner. The reducer function compares the accumulator (a) with the current element (e) and retains the larger value. The second parameter serves as the initial value for comparison, similar to the previous implementation:

function findMax(array) {
  return array.reduce((a, e) => a > e ? a : e, null);
}

let arr = [1, 3, 4, -2, -4, 8, 16, 0, -18, 6];
let empty = [];

console.log(findMax(arr));
console.log(findMax(empty));

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