Help me Return Largest Numbers in Arrays

JavaScript
1

Tell us what’s happening:

everything came out checked except the last largestOfFour([[17, 23, 25, 12], [25, 7, 34, 48], [4, -10, 18, 21], [-72, -3, -17, -10]]) should return [25, 48, 21, -3]. Can anyone tell me where i messed up?

Your code so far


function largestOfFour(arr) {
  var largestNumber = [0,0,0,0];// You can do this!
  for(var arrayIndex = 0; arrayIndex < arr.length; arrayIndex++){
    for(var subArrayIndex = 0; subArrayIndex < arr[arrayIndex].length; subArrayIndex++){
      if(arr[arrayIndex][subArrayIndex] > largestNumber[arrayIndex]){
        largestNumber[arrayIndex] = arr[arrayIndex][subArrayIndex];
      }
    }
  }
  return largestNumber;
}

largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-algorithm-scripting/return-largest-numbers-in-arrays/

3

It’s because of this line. You are initializing them with 0s and in the loop comparing them against 0. If you insert negative values, more specifically a negative value in your last item in the array, it will work.

For ex.

var largestNumber = [0,0,0,-Infinity];// You can do this!

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