2024?

2024/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "aoc_2024"
+version = "0.1.0"

2024/Cargo.toml

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+[package]
+name = "aoc_2024"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

2024/src/main.rs

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+mod day1input;
+
+use std::collections::HashMap;
+
+use day1input::INPUT;
+
+fn main() {
+    INPUT.lines().map(|line| {
+        let nums = line
+            .split("   ")
+            .map(|item| item.parse().expect("Input was not a valid number"))
+            .collect::<Vec<i32>>();
+        (nums[0], nums[1])
+    }).
+
+    // println!("Our Input\n\n{}", INPUT);
+    let mut left_column: Vec<i32> = vec![];
+    let mut right_column: Vec<i32> = vec![];
+
+    for line in INPUT.lines() {
+        let nums: Vec<i32> = line
+            .split("   ")
+            .map(|item| item.parse().expect("Input was not a valid number"))
+            .collect();
+        left_column.push(nums[0]);
+        right_column.push(nums[1]);
+    }
+
+    // Part 1
+    // left_column.sort();
+    // right_column.sort();
+    //
+    // let mut total_distance = 0;
+    // for i in 0..left_column.len() {
+    //     let distance = (left_column[i] - right_column[i]).abs();
+    //     total_distance += distance;
+    // }
+    // println!("part 1 answer: {}\n", total_distance);
+
+    // Part 2
+    // sodifjsdjif
+    let mut lookup: HashMap<i32, i32> = HashMap::new();
+    for n in right_column.iter() {
+        let count = lookup.entry(*n).or_insert(0);
+        *count += 1;
+    }
+
+    let mut sum = 0;
+    for n in left_column.iter() {
+        // how many times is `n` in the right column
+        let mut r = lookup.get(n).unwrap_or(&0); // O(1)
+        sum += n * r;
+    }
+    println!("part 2 answer: {}", sum);
+}