Khan Academy Binary Search Challenge

Binary Search (Array)

/* Returns either the index of the location in the array,
  or -1 if the array did not contain the targetValue */
var doSearch = function(array, targetValue) {
	var min = 0;
	var max = array.length - 1;
    var guess;
    var i = 1;
    
    while (max >= min){
        guess = Math.floor((max + min)/2);
        if(array[guess] === targetValue){
            println("Total guesses " +i);
         return guess;
        }
        else if (array[guess] < targetValue){
            min = guess +1;   
        }
        else {
            max = guess -1;   
        }
            i = i+1;
            println(guess);
    }


	return -1;
};

var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];

//var result = doSearch(primes, 5);
//println("Found prime at index " + result);


Program.assertEqual(doSearch(primes, 73), 20);
Program.assertEqual(doSearch(primes, 97), 24);
Program.assertEqual(doSearch(primes, 11), 4);

Program.assertEqual(doSearch(primes, 73), 20);
Program.assertEqual(doSearch(primes, 97), 24);
Program.assertEqual(doSearch(primes, 11), 4);

What do the arguments 20, 24 and 4 signify?

The second argument of Program.assertEqual refers to the number of the index in test example, index 18 has the prime number 67 and index 12 has the prime number 41.

• Program.assertEqual(doSearch(primes, 67), 18);//test

---

• Program.assertEqual(doSearch(primes, 41), 12);//test

---

var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97];

var doSearch = function(array, targetValue) {
	var min = 0;
	var max = array.length - 1;
        var guess;
        var intentos = 0;
    
      while(max >= min){ //stop loop if targetValue is not array
        intentos++;
        guess = Math.floor((min + max)/2);
        println(guess);
        if(targetValue === array[guess]){
            println("intentos realizados: " + intentos);
            return guess;
        }
        else if(array[guess] < targetValue){
            min = guess + 1;
        }
        else{  
            max = guess - 1;
        }
       
    }

	return -1;
};

var result = doSearch(primes, 41);
println("Found prime at index " + result);

Program.assertEqual(doSearch(primes, 73), 20);
Program.assertEqual(doSearch(primes, 67), 18);//test
Program.assertEqual(doSearch(primes, 41), 12);//test

Program.assertEqual(doSearch(primes, 73), 20);
Program.assertEqual(doSearch(primes, 97), 24);
Program.assertEqual(doSearch(primes, 11), 4);

What do the arguments 20, 24 and 4 signify?

the index of targetValue