From 7ad7138e93f14bae45398c17e7c7e00d99fe20c6 Mon Sep 17 00:00:00 2001
From: Kienan Stewart <kienan.stewart@burntworld.ca>
Date: Mon, 6 Dec 2021 22:35:42 -0500
Subject: [PATCH] Day 4

---
 day4/Cargo.lock  |   7 ++++
 day4/Cargo.toml  |   8 ++++
 day4/src/main.rs | 101 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+)
 create mode 100644 day4/Cargo.lock
 create mode 100644 day4/Cargo.toml
 create mode 100644 day4/src/main.rs

diff --git a/day4/Cargo.lock b/day4/Cargo.lock
new file mode 100644
index 0000000..e92c02c
--- /dev/null
+++ b/day4/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day4"
+version = "0.1.0"
diff --git a/day4/Cargo.toml b/day4/Cargo.toml
new file mode 100644
index 0000000..8842130
--- /dev/null
+++ b/day4/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "day4"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/day4/src/main.rs b/day4/src/main.rs
new file mode 100644
index 0000000..b05e60e
--- /dev/null
+++ b/day4/src/main.rs
@@ -0,0 +1,101 @@
+fn main() {
+    let min = [1, 9, 3, 6, 5, 1];
+    let max = [6, 4, 9, 7, 2, 9];
+
+    let mut matches = 0;
+    let mut i = min.clone();
+    loop {
+        // Check for a adjacents
+        if i[0] == i[1] ||
+            i[1] == i[2] ||
+            i[2] == i[3] ||
+            i[3] == i[4] ||
+            i[4] == i[5]
+        {
+            // Check for incrementing
+            if i[0] <= i[1] &&
+                i[1] <= i[2] &&
+                i[2] <= i[3] &&
+                i[3] <= i[4] &&
+                i[4] <= i[5]
+            {
+                //println!("{:?} matches", i);
+                matches += 1;
+            }
+        }
+        let mut x = 5;
+        loop {
+            i[x] += 1;
+            if i[x] >= 10 {
+                i[x] -= 10;
+                x -= 1;
+                continue
+            }
+            break;
+        }
+        if i[0] >= max[0] &&
+            i[1] >= max[1] &&
+            i[2] >= max[2] &&
+            i[3] >= max[3] &&
+            i[4] >= max[4] &&
+            i[5] >= max[5] {
+            break;
+        }
+    }
+    println!("[Part 1] There are {} potential matches", matches);
+
+    i = min.clone();
+    matches = 0;
+    loop {
+        // Check for incrementing
+        if i[0] <= i[1] &&
+            i[1] <= i[2] &&
+            i[2] <= i[3] &&
+            i[3] <= i[4] &&
+            i[4] <= i[5]
+        {
+            // Check for groups
+            let mut idx = 0;
+            let mut has_two_chain = false;
+            let mut chain_size = 1;
+            while idx < 5 {
+                if i[idx] == i[idx+1] {
+                    chain_size += 1;
+                    idx += 1;
+                }
+                else {
+                    if chain_size == 2 {
+                        has_two_chain = true;
+                    }
+                    chain_size = 1;
+                    idx += 1;
+                }
+            }
+            if chain_size == 2 {
+                has_two_chain = true;
+            }
+            if has_two_chain {
+                matches += 1;
+            }
+        }
+        let mut x = 5;
+        loop {
+            i[x] += 1;
+            if i[x] >= 10 {
+                i[x] -= 10;
+                x -= 1;
+                continue
+            }
+            break;
+        }
+        if i[0] >= max[0] &&
+            i[1] >= max[1] &&
+            i[2] >= max[2] &&
+            i[3] >= max[3] &&
+            i[4] >= max[4] &&
+            i[5] >= max[5] {
+            break;
+        }
+    }
+    println!("[Part 2] There are {} potential matches", matches);
+}