m2

src/m2.rs

@@ -1 +1,88 @@
+/// Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
+///
+///   1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
+///
+/// By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
+///
+/// ```rust
+/// use self::project_euler::m2::sum_of_even_fibonacci_sequence_less_than_4000000;
+/// assert_eq!(sum_of_even_fibonacci_sequence_less_than_4000000(), 4613732);
+/// ```
+pub fn sum_of_even_fibonacci_sequence_less_than_4000000() -> i64 {
+    let fib = |prepre: i64, pre: i64| -> (i64, i64) {
+        match (prepre, pre) {
+            (0, 0) => (0, 1),
+            (0, 1) => (1, 2),
+            // (1, 2) => (2, 3),
+            // (2, 3) => (3, 5),
+            // (3, 5) => (5, 8),
+            _ => (pre, prepre + pre),
+        }
+    };
 
+    let mut sum = 0;
+    let mut prepre = 0i64;
+    let mut pre = 0i64;
+    loop {
+        {
+            let tuple = fib(prepre, pre);
+            prepre = tuple.0;
+            pre = tuple.1;
+        }
+        println!("num {}", pre);
+        if pre > 4_000_000 {
+            break;
+        }
+        if pre % 2 == 0 {
+            sum += pre;
+        }
+    }
+    sum
+}
+
+/// Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
+///
+///   (0, 1,)1,| 2, 3, 5,| 8, 13, 21,| 34, 55, 89, ...
+///
+/// By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
+///
+/// ```rust
+/// use self::project_euler::m2::sum_of_even_fibonacci_sequence_less_than_4000000_011_235_8;
+/// assert_eq!(sum_of_even_fibonacci_sequence_less_than_4000000_011_235_8(), 4613732);
+/// ```
+pub fn sum_of_even_fibonacci_sequence_less_than_4000000_011_235_8() -> i64 {
+    let fib = |preprepre: i64, prepre: i64, pre: i64| -> (i64, i64, i64) {
+        match (preprepre, prepre, pre) {
+            (0, 1, 1) => (2, 3, 5),
+            // (2,  3,  5) => ( 8, 13, 21),
+            // (8, 13, 21) => (34, 55, 89),
+            _ => {
+                let post = prepre + pre;
+                let postpost = pre + post;
+                let postpostpost = post + postpost;
+                (post, postpost, postpostpost)
+            }
+        }
+    };
+
+    let mut sum = 0;
+    let mut preprepre = 0i64;
+    let mut prepre = 1i64;
+    let mut pre = 1i64;
+    loop {
+        {
+            let tuple = fib(preprepre, prepre, pre);
+            preprepre = tuple.0;
+            prepre = tuple.1;
+            pre = tuple.2
+        }
+        println!("num {}", preprepre);
+        if preprepre > 4_000_000 {
+            break;
+        }
+        if preprepre % 2 == 0 {
+            sum += preprepre;
+        }
+    }
+    sum
+}