From 7cb548a8e5969121bf3d295c23bb650282772681 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert.ljpeters@gmail.com>
Date: Mon, 5 Dec 2016 23:54:19 +0100
Subject: [PATCH] Solution to day 5.

---
 2016/day-05/Cargo.toml  |  7 +++++
 2016/day-05/src/main.rs | 65 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 2016/day-05/Cargo.toml
 create mode 100644 2016/day-05/src/main.rs

diff --git a/2016/day-05/Cargo.toml b/2016/day-05/Cargo.toml
new file mode 100644
index 0000000..e6fa64e
--- /dev/null
+++ b/2016/day-05/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "day-05"
+version = "0.1.0"
+authors = ["Bert Peters <bert.ljpeters@gmail.com>"]
+
+[dependencies]
+rust-crypto = "^0.2"
diff --git a/2016/day-05/src/main.rs b/2016/day-05/src/main.rs
new file mode 100644
index 0000000..bca2ecd
--- /dev/null
+++ b/2016/day-05/src/main.rs
@@ -0,0 +1,65 @@
+extern crate crypto;
+
+use crypto::md5::Md5;
+use crypto::digest::Digest;
+
+fn find_hash(word: &str, mut start: i32) -> (char, char, i32)
+{
+    let mut hasher = Md5::new();
+    loop {
+        let num = start.to_string();
+        hasher.reset();
+        hasher.input_str(word);
+        hasher.input_str(&num);
+
+        let hash = hasher.result_str();
+        if &hash[0..5] == "00000" {
+            return (hash.chars().nth(5).unwrap(), hash.chars().nth(6).unwrap(), start);
+        }
+
+        start += 1;
+    }
+}
+
+fn valid_pos(c: char) -> bool
+{
+    '0' <= c && c <= '7'
+}
+
+fn pos(c: char) -> i32
+{
+    ((c as u8) - ('0' as u8)) as i32
+}
+
+fn main() {
+    let input = "cxdnnyjw";
+
+    let mut start = 0;
+    let mut password = ['-'; 8];
+    let mut used = [false; 8];
+
+    let mut found = 0;
+    let mut printed = 0;
+
+    while found < 8 {
+        let (c1, c2, num) = find_hash(input, start);
+        start = num + 1;
+
+        if valid_pos(c1) {
+            let p = pos(c1) as usize;
+            if !used[p] {
+                found += 1;
+                password[p] = c2;
+                used[p] = true;
+            }
+        }
+
+        if printed < 8 {
+            print!("{}", c1);
+            printed += 1;
+        }
+    }
+
+    let result: String = password.iter().cloned().collect();
+    println!("\n{}", result);
+}