2016/07

2016/07/src/main.rs

@@ -0,0 +1,233 @@
+use std::collections::{VecDeque, HashSet};
+use std::io::{self, BufRead};
+
+
+struct TLSBuffer {
+    vec: VecDeque<char>
+}
+
+impl TLSBuffer {
+    fn new() -> Self {
+        TLSBuffer {
+            vec: VecDeque::with_capacity(4)
+        }
+    }
+
+    fn push(&mut self, value: char) {
+        self.vec.push_back(value);
+
+        while self.vec.len() > 4 {
+            self.vec.pop_front();
+        }
+    }
+
+    fn clear(&mut self) {
+        self.vec.clear();
+    }
+
+    fn is_abba(&self) -> bool {
+        self.vec.len() == 4
+            && self.vec[0] != self.vec[1]
+            && self.vec[0] == self.vec[3]
+            && self.vec[1] == self.vec[2]
+    }
+}
+
+
+struct SSLBuffer {
+    vec: VecDeque<char>
+}
+
+impl SSLBuffer {
+    fn new() -> Self {
+        SSLBuffer {
+            vec: VecDeque::with_capacity(3)
+        }
+    }
+
+    fn push(&mut self, value: char) {
+        self.vec.push_back(value);
+
+        while self.vec.len() > 3 {
+            self.vec.pop_front();
+        }
+    }
+
+    fn clear(&mut self) {
+        self.vec.clear();
+    }
+
+    fn is_aba(&self) -> bool {
+        self.vec.len() == 3
+            && self.vec[0] != self.vec[1]
+            && self.vec[0] == self.vec[2]
+    }
+
+    fn get_aba(&self) -> String {
+        format!("{}{}{}", self.vec[0], self.vec[1], self.vec[0])
+    }
+
+    fn get_bab(&self) -> String {
+        format!("{}{}{}", self.vec[1], self.vec[0], self.vec[1])
+    }
+}
+
+
+enum MachineState {
+    Default,
+    HypernetSequence
+}
+
+
+fn supports_tls(input: &str) -> bool {
+    let mut state = MachineState::Default;
+
+    let mut buffer = TLSBuffer::new();
+    let mut supports_tls = false;
+
+    for ch in input.chars() {
+        state = match (ch, state) {
+            ('[', MachineState::Default) => {
+                buffer.clear();
+
+                MachineState::HypernetSequence
+            }
+            (ch, MachineState::Default) => {
+                buffer.push(ch);
+
+                if buffer.is_abba() {
+                    supports_tls = true;
+                }
+
+                MachineState::Default
+            }
+
+            (']', MachineState::HypernetSequence) => {
+                buffer.clear();
+
+                MachineState::Default
+            }
+            (ch, MachineState::HypernetSequence) => {
+                buffer.push(ch);
+
+                if buffer.is_abba() {
+                    return false;
+                }
+
+                MachineState::HypernetSequence
+            }
+        }
+    }
+
+    supports_tls
+}
+
+fn supports_ssl(input: &str) -> bool {
+    let mut state = MachineState::Default;
+
+    let mut buffer = SSLBuffer::new();
+
+    let mut aba = HashSet::new();
+    let mut bab = HashSet::new();
+
+    for ch in input.chars() {
+        state = match (ch, state) {
+            ('[', MachineState::Default) => {
+                buffer.clear();
+
+                MachineState::HypernetSequence
+            }
+            (ch, MachineState::Default) => {
+                buffer.push(ch);
+
+                if buffer.is_aba() {
+                    aba.insert(buffer.get_aba());
+                }
+
+                MachineState::Default
+            }
+
+            (']', MachineState::HypernetSequence) => {
+                buffer.clear();
+
+                MachineState::Default
+            }
+            (ch, MachineState::HypernetSequence) => {
+                buffer.push(ch);
+
+                if buffer.is_aba() {
+                    bab.insert(buffer.get_bab());
+                }
+
+                MachineState::HypernetSequence
+            }
+        }
+    }
+
+    aba.intersection(&bab).count() > 0
+}
+
+fn main() {
+    let stdin = io::stdin();
+
+    let lines = stdin.lock().lines()
+        .filter_map(|line| line.ok())
+        .collect::<Vec<_>>();
+
+    let count_tls = lines.iter()
+        .filter(|line| supports_tls(&line))
+        .count();
+
+    let count_ssl = lines.iter()
+        .filter(|line| supports_ssl(&line))
+        .count();
+
+    println!("count_tls={}", count_tls);
+    println!("count_ssl={}", count_ssl);
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::{supports_tls, supports_ssl};
+
+    #[test]
+    fn example_01() {
+        assert_eq!(true, supports_tls("abba[mnop]qrst"));
+    }
+
+    #[test]
+    fn example_02() {
+        assert_eq!(false, supports_tls("abcd[bddb]xyyx"));
+    }
+
+    #[test]
+    fn example_03() {
+        assert_eq!(false, supports_tls("aaaa[qwer]tyui"));
+    }
+
+    #[test]
+    fn example_04() {
+        assert_eq!(true, supports_tls("ioxxoj[asdfgh]zxcvbn"));
+    }
+
+    #[test]
+    fn example_05() {
+        assert_eq!(true, supports_ssl("aba[bab]xyz"));
+    }
+
+    #[test]
+    fn example_06() {
+        assert_eq!(false, supports_ssl("xyx[xyx]xyx"));
+    }
+
+    #[test]
+    fn example_07() {
+        assert_eq!(true, supports_ssl("aaa[kek]eke"));
+    }
+
+    #[test]
+    fn example_08() {
+        assert_eq!(true, supports_ssl("zazbz[bzb]cdb"));
+    }
+}