Question

I need a more optimized version of this javascript code to find the 3 largest values in an array. I need to get the indexes of the largest numbers. Are there any other easier methods to solve the problem?

var maxIndex = new Array();
var maxPoints = new Array();
var scoreByPattern = new Array(93, 17, 56, 91, 98, 33, 9, 38, 55, 78, 29, 81, 60);

function findLargest3() {
  maxPoints[0] = 0;
  maxPoints[1] = 0;
  maxPoints[2] = 0; 
  
  for (i = 0; i < scoreByPattern.length; i++) {
    if (scoreByPattern[i] > maxPoints[0]) {
      maxPoints[0] = scoreByPattern[i];
      maxIndex[0] = i;
    }
  }

  for (i = 0; i < scoreByPattern.length; i++) {
    if (scoreByPattern[i] > maxPoints[1] && scoreByPattern[i] < maxPoints[0]) {
      maxPoints[1] = scoreByPattern[i];
      maxIndex[1] = i;
    }
  }

  for (i = 0; i < scoreByPattern.length; i++) {
    if (scoreByPattern[i] > maxPoints[2] && scoreByPattern[i] < maxPoints[1]) {
      maxPoints[2] = scoreByPattern[i];
      maxIndex[2] = i;
    }
  }

  console.log(scoreByPattern + "/******/" + maxPoints[0] + "/" + maxPoints[1] + "/" + maxPoints[2]);
  //alert(maxIndex);
}

findLargest3();

Answer 1

You can sort the array descending. Then the indexes of the highest 3 values will be the first three items in the array. You can access them individually or use slice() to get them at once. The example below shows both methods.

var maxPoints = new Array();
var scoreByPattern = new Array(93, 17, 56, 91, 98, 33, 9, 38, 55, 78, 29, 81, 60);

findLargest3();

function findLargest3() {
  scoreByPattern.sort((a, b) => a < b ? 1 : a > b ? -1 : 0);
  
  console.log(scoreByPattern + "/******/" + scoreByPattern[0] + "/" + scoreByPattern[1] + "/" + scoreByPattern[2]);  
  console.log(scoreByPattern.slice(0, 3));
}