solutions: 1-3

even_fibonacci_numbers.rs

@@ -0,0 +1,16 @@
+fn main() {
+    let mut sequence: Vec<i32> = vec![1, 2];
+    while sequence[sequence.len()-1] <= 4000000 {
+        let mut last = sequence[sequence.len()-1];
+        let mut secondlast = sequence[sequence.len()-2];
+        (secondlast, last) = (last, secondlast+last);
+        sequence.push(last);
+    }
+    for i in sequence.clone() {
+        if i % 2 != 0 || i > 4000000 {
+            sequence.remove(sequence.iter().position(|x| *x == i).expect("Item not found"));
+        }
+    }
+    let sum: i32 = sequence.iter().sum();
+    println!("{}", sum);
+}

largest_prime_factor.rs

@@ -0,0 +1,18 @@
+fn main() {
+    let mut num: u64 = 600851475143;
+    let mut factors: Vec<u64> = vec![];
+    let mut i: u64 = 2;
+    while i.pow(2) <= num {
+            if num % i == 0 {
+                factors.push(i);
+                num = (num as f64 / i as f64).floor() as u64;
+            } else {
+                i += 1;
+            }
+    }
+    if num != 1 {
+        factors.push(num);
+    }
+
+    println!("{:?}", factors);
+}

multiples_of_3_or_5.rs

@@ -0,0 +1,12 @@
+fn main() {
+    let mut multiples: Vec<i32> = vec![];
+    for num in 0..1000 {
+        if num % 3 == 0 {
+            multiples.push(num);
+        } else if num % 5 == 0 {
+            multiples.push(num);
+        }
+    }
+    let sum: i32 = multiples.iter().sum();
+    println!("{}", sum);
+}