Mar 24, 2020 · Mar 24, 2020
diff --git a/src/main/java/com/fishercoder/solutions/_204.java b/src/main/java/com/fishercoder/solutions/_204.java
 But don't let that name scare you, I promise that the concept is surprisingly simple.

 Sieve of Eratosthenes: algorithm steps for primes below 121. "Sieve of Eratosthenes Animation" by SKopp is licensed under CC BY 2.0.
 We start off with a table of n numbers. Let's look at the first number, 2. We know all multiples of 2 must not be primes, so we mark them off as non-primes. Then we look at the next number, 3. Similarly, all multiples of 3 such as 3 × 2 = 6, 3 × 3 = 9, ... must not be primes, so we mark them off as well. Now we look at the next number, 4, which was already marked off.
 We start off with a table of n numbers. Let's look at the first number, 2. We know all multiples of 2 must not be primes, so we mark
 them off as non-primes. Then we look at the next number, 3. Similarly, all multiples of 3 such as 3 × 2 = 6, 3 × 3 = 9, ... must not
 be primes, so we mark them off as well. Now we look at the next number, 4, which was already marked off.
 What does this tell you? Should you mark off all multiples of 4 as well?
 4 is not a prime because it is divisible by 2, which means all multiples of 4 must also be divisible by 2 and were already marked off.
 So we can skip 4 immediately and go to the next number, 5.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -48,7 +48,9 @@ private boolean isPrime(int num) {
		But don't let that name scare you, I promise that the concept is surprisingly simple.

		Sieve of Eratosthenes: algorithm steps for primes below 121. "Sieve of Eratosthenes Animation" by SKopp is licensed under CC BY 2.0.
		We start off with a table of n numbers. Let's look at the first number, 2. We know all multiples of 2 must not be primes, so we mark them off as non-primes. Then we look at the next number, 3. Similarly, all multiples of 3 such as 3 × 2 = 6, 3 × 3 = 9, ... must not be primes, so we mark them off as well. Now we look at the next number, 4, which was already marked off.
		We start off with a table of n numbers. Let's look at the first number, 2. We know all multiples of 2 must not be primes, so we mark
		them off as non-primes. Then we look at the next number, 3. Similarly, all multiples of 3 such as 3 × 2 = 6, 3 × 3 = 9, ... must not
		be primes, so we mark them off as well. Now we look at the next number, 4, which was already marked off.
		What does this tell you? Should you mark off all multiples of 4 as well?
		4 is not a prime because it is divisible by 2, which means all multiples of 4 must also be divisible by 2 and were already marked off.
		So we can skip 4 immediately and go to the next number, 5.
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