From 4b29a4b04f643d8406859ab8624414d809100c60 Mon Sep 17 00:00:00 2001
From: Joseph Chamochumbi <sephxd1234@gmail.com>
Date: Tue, 7 Dec 2021 07:07:14 +0100
Subject: [PATCH] feat: Day 7 2021, :star: :star: :fish:

---
 2021/day-7/Cargo.toml  |   9 ++++
 2021/day-7/src/main.rs | 107 +++++++++++++++++++++++++++++++++++++++++
 2021/deno/day-7.ts     |  47 ++++++++++++++++++
 3 files changed, 163 insertions(+)
 create mode 100644 2021/day-7/Cargo.toml
 create mode 100644 2021/day-7/src/main.rs
 create mode 100644 2021/deno/day-7.ts

diff --git a/2021/day-7/Cargo.toml b/2021/day-7/Cargo.toml
new file mode 100644
index 0000000..37b2a4d
--- /dev/null
+++ b/2021/day-7/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+authors = ["Joseph Chamochumbi <sephxd1234@gmail.com>"]
+edition = "2018"
+name = "day-7"
+version = "0.1.0"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[dependencies]
+aoc = {git = "https://github.com/icyJoseph/advent-of-code.git"}
diff --git a/2021/day-7/src/main.rs b/2021/day-7/src/main.rs
new file mode 100644
index 0000000..bf98bc6
--- /dev/null
+++ b/2021/day-7/src/main.rs
@@ -0,0 +1,107 @@
+use aoc;
+
+fn solve(raw: String) -> () {
+    let positions = raw
+        .trim()
+        .split(",")
+        .map(|x| parse_num::<u32>(x))
+        .collect::<Vec<u32>>();
+
+    let max_position = *positions.iter().max().unwrap();
+
+    let simple_fuel_calc = |target: u32| {
+        positions
+            .iter()
+            .map(|curr| {
+                if curr > &target {
+                    curr - target
+                } else {
+                    target - curr
+                }
+            })
+            .sum()
+    };
+
+    let comp_fuel_calc = |target: u32| {
+        positions
+            .iter()
+            .map(|curr| {
+                let diff = if curr > &target {
+                    curr - target
+                } else {
+                    target - curr
+                };
+
+                diff * (diff + 1) / 2
+            })
+            .sum()
+    };
+
+    let calc_lowest_fuel = |aggregator: Box<dyn Fn(u32) -> u32>| {
+        let mut lowest: Option<u32> = None;
+
+        for pos in 0..=max_position {
+            match lowest {
+                Some(n) => {
+                    let fuel = aggregator(pos);
+                    if fuel < n {
+                        lowest = Some(fuel);
+                    }
+                }
+                _ => lowest = Some(aggregator(pos)),
+            }
+        }
+
+        lowest
+    };
+
+    let part_one = calc_lowest_fuel(Box::new(simple_fuel_calc));
+
+    let part_two = calc_lowest_fuel(Box::new(comp_fuel_calc));
+
+    println!("Part one: {}", part_one.unwrap_or(0));
+
+    println!("Part two: {}", part_two.unwrap_or(0));
+}
+
+fn main() {
+    let input = aoc::get_input(2021, 7);
+
+    // let input = std::fs::read_to_string("./input/day-7.in").expect("Error reading input");
+
+    solve(input);
+}
+
+// Utilities
+#[allow(dead_code)]
+fn normal(x: usize, y: usize, width: usize) -> usize {
+    x + y * width
+}
+
+#[allow(dead_code)]
+fn rev_normal(norm: usize, width: usize) -> (usize, usize) {
+    (norm % width, norm / width)
+}
+
+#[allow(dead_code)]
+fn parse_num<T: std::str::FromStr>(str: &str) -> T {
+    match str.trim().parse::<T>() {
+        Ok(n) => n,
+        _ => panic!("Error parsing"),
+    }
+}
+#[allow(dead_code)]
+fn to_int(bin: &str) -> u32 {
+    match u32::from_str_radix(bin, 2) {
+        Ok(n) => n,
+        _ => panic!("Error parsing binary to integer"),
+    }
+}
+
+#[allow(dead_code)]
+fn string_vec<T: std::string::ToString>(vec: &Vec<T>, separator: &str) -> String {
+    vec.iter()
+        .map(|x| x.to_string())
+        .collect::<Vec<String>>()
+        .join(separator)
+}
diff --git a/2021/deno/day-7.ts b/2021/deno/day-7.ts
new file mode 100644
index 0000000..003ee5b
--- /dev/null
+++ b/2021/deno/day-7.ts
@@ -0,0 +1,47 @@
+const input = await Deno.readTextFile("./input/day-7.in");
+
+const positions = input.split(",").map(Number);
+
+const sorted = positions.sort((a, b) => a - b);
+
+const length = sorted.length;
+
+const median =
+  length % 2 === 0
+    ? Math.floor((sorted[length / 2] + sorted[length / 2 - 1]) / 2)
+    : sorted[Math.floor(length / 2)];
+
+const total = sorted.reduce((prev, curr) => {
+  return prev + Math.abs(curr - median);
+}, 0);
+
+/**
+ * Part One
+ */
+console.log("Part One:", total);
+
+/**
+ * Part Two
+ */
+
+const maxPos = Math.max(...positions);
+
+let superTotal = Infinity;
+let current = sorted[0];
+
+while (current <= maxPos) {
+  const next = sorted.reduce((prev, x) => {
+    const diff = Math.abs(x - current);
+    const accumulated = (diff * (diff + 1)) / 2;
+
+    return prev + accumulated;
+  }, 0);
+
+  if (next < superTotal) {
+    superTotal = next;
+  }
+
+  current += 1;
+}
+
+console.log("Part Two:", superTotal);