From 01e0b25f8202e975ca3a2264c86e61e388e135db Mon Sep 17 00:00:00 2001
From: Bert Peters <bert.ljpeters@gmail.com>
Date: Thu, 15 Dec 2016 21:16:42 +0100
Subject: [PATCH] Add solutions for day 14.

Much hash. Very memoize.
---
 2016/day-14/Cargo.toml  |   7 +++
 2016/day-14/src/main.rs | 130 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 137 insertions(+)
 create mode 100644 2016/day-14/Cargo.toml
 create mode 100644 2016/day-14/src/main.rs

diff --git a/2016/day-14/Cargo.toml b/2016/day-14/Cargo.toml
new file mode 100644
index 0000000..58bd76a
--- /dev/null
+++ b/2016/day-14/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "day-14"
+version = "0.1.0"
+authors = ["Bert Peters <bert.ljpeters@gmail.com>"]
+
+[dependencies]
+rust-crypto = "^0.2"
diff --git a/2016/day-14/src/main.rs b/2016/day-14/src/main.rs
new file mode 100644
index 0000000..dd08e44
--- /dev/null
+++ b/2016/day-14/src/main.rs
@@ -0,0 +1,130 @@
+extern crate crypto;
+
+use crypto::md5::Md5;
+use crypto::digest::Digest;
+use std::collections::HashMap;
+
+const INPUT: &'static str =  "ihaygndm";
+
+fn get_hash(n: i32, sieve: &mut HashMap<i32, String>) -> String
+{
+    if !sieve.contains_key(&n) {
+        let mut hasher = Md5::new();
+        hasher.input_str(INPUT);
+        hasher.input_str(&n.to_string());
+
+        let result = String::from(hasher.result_str());
+        sieve.insert(n, result);
+    }
+
+    return sieve[&n].clone();
+}
+
+fn contains_3(data: &str) -> Option<char>
+{
+    let mut cur = 1;
+    let mut prev = '\0';
+    for c in data.chars() {
+        if c == prev {
+            cur += 1;
+            if cur == 3 {
+                return Some(c);
+            }
+        } else {
+            prev = c;
+            cur = 1;
+        }
+    }
+
+    return None;
+}
+
+fn get_hash2(n: i32, sieve: &mut HashMap<i32, String>) -> String
+{
+    if !sieve.contains_key(&n) {
+        let mut cur = String::from(INPUT);
+        cur += &n.to_string();
+        for _ in 0..2017 {
+            let mut hasher = Md5::new();
+            hasher.input_str(&cur);
+            cur = String::from(hasher.result_str());
+        }
+        sieve.insert(n, cur);
+    }
+
+    return sieve[&n].clone();
+}
+
+fn part1()
+{
+    let mut n = 0;
+    let mut found = 0;
+    let mut sieve = HashMap::new();
+
+    loop {
+        let cur = get_hash(n, &mut sieve);
+
+        match contains_3(&cur) {
+            Some(c) => {
+                let search: String = (0..5).map(|_| c).collect();
+                for i in 1..1001 {
+                    let opt = get_hash(n + i, &mut sieve);
+
+                    if opt.contains(&search) {
+                        found += 1;
+                        break;
+                    }
+                }
+
+                if found == 64 {
+                    println!("Found 64 keys at index {}", n);
+                    return;
+                }
+
+            },
+            _ => {},
+        }
+
+        n += 1;
+    }
+}
+
+fn part2()
+{
+    let mut n = 0;
+    let mut found = 0;
+    let mut sieve = HashMap::new();
+
+    loop {
+        let cur = get_hash2(n, &mut sieve);
+
+        match contains_3(&cur) {
+            Some(c) => {
+                let search: String = (0..5).map(|_| c).collect();
+                for i in 1..1001 {
+                    let opt = get_hash2(n + i, &mut sieve);
+
+                    if opt.contains(&search) {
+                        found += 1;
+                        break;
+                    }
+                }
+
+                if found == 64 {
+                    println!("Found 64 keys at index {}", n);
+                    return;
+                }
+
+            },
+            _ => {},
+        }
+
+        n += 1;
+    }
+}
+
+
+fn main() {
+    part1();
+    part2();
+}