Create 3-largest_prime_factor.js

3-largest_prime_factor.js

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+let primeFactors = []
+
+let generatePrimeFactors = (number) => {
+
+  // Qutiient keeps track of result after division
+  let quotient = number
+
+  /* If Even, keep dividing by two */
+  while(quotient % 2 === 0){
+    primeFactors.push(2)
+    quotient = quotient / 2
+  }
+
+  /* Quotient is odd at this point, so now find odd prime factors */
+  let i
+  // Look through odd numbers between 3 and quotient
+  for(i = 3; i < quotient; i = i + 2){
+    // If we can quotient by the odd number without a remainder, divide it
+    while(quotient % i === 0){
+      primeFactors.push(i)
+      quotient = quotient / i
+    }
+  }
+  // If the remaining quotient is a prime number, push to array
+  if(quotient !== 1){
+    primeFactors.push(quotient)
+  }
+
+}
+
+/* Solution Function */
+let largestPrimeFactor = (number) => {
+
+  generatePrimeFactors(number)
+
+  // Converts array into series of function arguments fed into Math.max
+  return Math.max(...primeFactors)
+}
+
+
+/* Check Solution */
+console.log(largestPrimeFactor(600851475143))