2015/08

2015/08/src/main.rs

@@ -0,0 +1,118 @@
+use std::io::{self, BufRead};
+use std::str;
+
+
+#[derive(Debug)]
+enum StateMachine {
+    Normal,
+    Escape,
+    Hexadecimal(u8)
+}
+
+fn memory_length(input: &str) -> usize {
+    let mut count: usize = 0;
+
+    let mut state = StateMachine::Normal;
+
+    for c in input.chars() {
+        state = match (c, state) {
+            // Normal.
+            ('\\', StateMachine::Normal) => {
+                StateMachine::Escape
+            }
+            (_, s @ StateMachine::Normal) => {
+                count += 1;
+
+                s
+            }
+
+            // Escape.
+            ('x', StateMachine::Escape) => {
+                StateMachine::Hexadecimal(1)
+            }
+            (_, StateMachine::Escape) => {
+                count += 1;
+
+                StateMachine::Normal
+            }
+
+            // Hexadecimal.
+            (_, StateMachine::Hexadecimal(mut hex)) => {
+                if hex == 2 {
+                    count += 1;
+
+                    StateMachine::Normal
+                } else {
+                    hex += 1;
+
+                    StateMachine::Hexadecimal(hex)
+                }
+            }
+        };
+
+        // println!("{} - {} => {:?}", count, c, state);
+    }
+
+    count - 2
+}
+
+fn code_length(input: &str) -> usize {
+    input.len()
+}
+
+fn main() {
+    let stdin = io::stdin();
+
+    let lines = stdin.lock().lines()
+        .filter_map(|line| line.ok())
+        .collect::<Vec<_>>();
+
+    let count_1: usize = lines.iter()
+        .map(|line| code_length(&line))
+        .sum();
+
+    let count_2: usize = lines.iter()
+        .map(|line| memory_length(&line))
+        .sum();
+
+    println!("count_1={}", count_1);
+    println!("count_2={}", count_1 - count_2);
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::{code_length, memory_length};
+
+    #[test]
+    fn example_01() {
+        let line = r#""""#;
+
+        assert_eq!(2, code_length(line));
+        assert_eq!(0, memory_length(line));
+    }
+
+    #[test]
+    fn example_02() {
+        let line = r#""abc""#;
+
+        assert_eq!(5, code_length(line));
+        assert_eq!(3, memory_length(line));
+    }
+
+    #[test]
+    fn example_03() {
+        let line = r#""aaa\"aaa""#;
+
+        assert_eq!(10, code_length(line));
+        assert_eq!(7, memory_length(line));
+    }
+
+    #[test]
+    fn example_04() {
+        let line = r#""\x27""#;
+
+        assert_eq!(6, code_length(line));
+        assert_eq!(1, memory_length(line));
+    }
+}