correctly label euler solutions

examples/puzzles/euler_02.zr

@@ -1,21 +1,13 @@
-func num_divisors[n: i64] : i64
-    let end: i64 = math.isqrt(n)
-
-    let out: i64 = 0
-    for i in 1..end+1
-        if n % i == 0
-            out = out + 2
-
-    if end * end == n
-        out = out - 1
-    return out
-
 func main[] : i64
-    let n: i64 = 0
-    let i: i64 = 1
-    while true
-        n = n + i
-        if num_divisors(n) > 500
-            io.println_i64(n)
-            break
-        i = i + 1
+    let sum: i64 = 0
+    let a: i64 = 0
+    let b: i64 = 1
+
+    while a < 4000000
+        if a % 2 == 0
+            sum = sum + a
+        let temp: i64 = b
+        b = a + b
+        a = temp
+
+    io.println_i64(sum)