feat: upload day 7

Author: Nitestack

2024/day-7/Cargo.lock

@@ -0,0 +1,6 @@
+[package]
+name = "day-7"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

2024/day-7/Cargo.toml

@@ -0,0 +1,48 @@
+// ╭─────────────────────────────────────────────────────────╮
+// │ Advent of Code 2024 - Day 7                             │
+// ╰─────────────────────────────────────────────────────────╯
+
+fn main() {
+    let input = include_str!("../input.txt");
+
+    // ── Part 1 ──────────────────────────────────────────────────────────
+    let result_part1 = input.lines().map(|line| {
+        let (unparsed_result, unparsed_numbers) = line.split_once(": ").expect("Invalid input");
+        let result = unparsed_result.parse::<usize>().unwrap();
+        let numbers = unparsed_numbers.split(" ")
+            .map(|unparsed_number| unparsed_number.parse::<usize>().unwrap())
+            .collect::<Vec<_>>();
+        if try_numbers(&numbers[1..], result, numbers[0]) { result } else { 0 }
+    }).sum::<usize>();
+    println!("Result: {result_part1}");
+    // ── Part 2 ──────────────────────────────────────────────────────────
+    let result_part2 = input.lines().map(|line| {
+        let (unparsed_result, unparsed_numbers) = line.split_once(": ").expect("Invalid input");
+        let result = unparsed_result.parse::<usize>().unwrap();
+        let numbers = unparsed_numbers.split(" ")
+            .map(|unparsed_number| unparsed_number.parse::<usize>().unwrap())
+            .collect::<Vec<_>>();
+        if try_numbers2(&numbers[1..], result, numbers[0]) { result } else { 0 }
+    }).sum::<usize>();
+    println!("Result: {result_part2}");
+}
+
+fn try_numbers(numbers: &[usize], result: usize, current: usize) -> bool {
+    if numbers.is_empty() {
+        result == current
+    } else if current > result {
+        false
+    } else {
+        try_numbers(&numbers[1..], result, current + numbers[0]) || try_numbers(&numbers[1..], result, current * numbers[0])
+    }
+}
+
+fn try_numbers2(numbers: &[usize], result: usize, current: usize) -> bool {
+    if numbers.is_empty() {
+        result == current
+    } else if current > result {
+        false
+    } else {
+        try_numbers2(&numbers[1..], result, current + numbers[0]) || try_numbers2(&numbers[1..], result, current * numbers[0]) || try_numbers2(&numbers[1..], result, current * 10usize.pow(numbers[0].ilog10() + 1) + numbers[0])
+    }
+}