Add solution to day 7.

2016/day-07/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day-07"
+version = "0.1.0"
+authors = ["Bert Peters <bert.ljpeters@gmail.com>"]
+
+[dependencies]

2016/day-07/sample.txt

@@ -0,0 +1,8 @@
+abba[mnop]qrst
+abcd[bddb]xyyx
+aaaa[qwer]tyui
+ioxxoj[asdfgh]zxcvbn
+aba[bab]xyz
+xyx[xyx]xyx
+aaa[kek]eke
+zazbz[bzb]cdb

2016/day-07/src/main.rs

@@ -0,0 +1,99 @@
+use std::collections::VecDeque;
+use std::env;
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::fs::File;
+
+fn is_tls(line: &str) -> bool
+{
+    let mut last = VecDeque::new();
+    let mut in_brackets = false;
+    let mut found = false;
+
+    for c in line.chars() {
+
+        match c {
+            '[' => {
+                in_brackets = true;
+                last = VecDeque::new();
+            },
+            ']' => {
+                in_brackets = false;
+                last = VecDeque::new();
+            },
+            _ => {
+                last.push_back(c);
+                if last.len() >= 4 {
+                    if last[0] == last[3] && last[1] == last[2] && last[0] != last[1] {
+                        found = true;
+                        if in_brackets {
+                            return false;
+                        }
+                    }
+                    last.pop_front();
+                }
+            },
+        }
+    }
+
+    return found;
+}
+
+fn is_ssl(line: &str) -> bool
+{
+    let parts: Vec<&str> = line.split(|c| c == '[' || c == ']').collect();
+
+    for (i, part) in parts.iter().enumerate() {
+        if i % 2 != 0 {
+            continue;
+        }
+
+        let mut last = VecDeque::new();
+        for c in part.chars() {
+            last.push_back(c);
+            if last.len() >= 3 {
+                if last[0] == last[2] && last[0] != last[1] {
+                    let mut identifier = String::new();
+                    identifier.push(last[1]);
+                    identifier.push(last[0]);
+                    identifier.push(last[1]);
+
+                    for (j, bracket) in parts.iter().enumerate() {
+                        if j % 2 == 0 {
+                            continue;
+                        }
+
+                        if bracket.contains(&identifier) {
+                            return true;
+                        }
+                    }
+                }
+
+                last.pop_front();
+            }
+        }
+    }
+
+    return false;
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    let f = File::open(&args[1]).expect("Could not open file");
+    let reader = BufReader::new(f);
+
+    let mut tls = 0;
+    let mut ssl = 0;
+    for line in reader.lines() {
+        let content = line.unwrap();
+        if is_tls(&content) {
+            tls += 1;
+        }
+        if is_ssl(&content) {
+            ssl += 1;
+        }
+    }
+
+    println!("{} addresses are tls", tls);
+    println!("{} addresses are ssl", ssl);
+}