day_7: done for small numbers

Cargo.lock

@@ -6,6 +6,7 @@ version = 3
 name = "advent-of-code-2024"
 version = "0.1.0"
 dependencies = [
+ "primes",
  "regex",
 ]
 
@@ -24,6 +25,12 @@ version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
+[[package]]
+name = "primes"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0466ef49edd4a5a4bc9d62804a34e89366810bd8bfc3ed537101e3d099f245c5"
+
 [[package]]
 name = "regex"
 version = "1.11.1"

Cargo.toml

@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+primes = "0.4.0"
 regex = "1.11.1"

README.md

@@ -9,7 +9,7 @@ https://adventofcode.com/2024
 | 04 | Ceres Search | :pushpin: | :pushpin: | Matrix multidirectional search |
 | 05 | Print Queue | :pushpin: | :pushpin: | Queue order |
 | 06 | Guard Gallivant | :pushpin: | :pushpin: | 2D navigation |
-| 07 |  |  |  | |
+| 07 | Bridge Repair |  |  | Equation parsing |
 | 08 |  |  |  | |
 | 09 |  |  |  | |
 | 10 |  |  |  | |

assets/day_7_calibrations_input

@@ -0,0 +1,9 @@
+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20

src/advent_of_code/mod.rs

@@ -1,11 +1,12 @@
-mod fri_06;
+// mod fri_06;
-mod mon_02;
+// mod mon_02;
-mod sun_01;
+// mod sun_01;
-mod thu_05;
+// mod thu_05;
-mod tue_03;
+// mod tue_03;
+// mod wed_04;
+mod sat_07;
 mod types;
 mod utils;
-mod wed_04;
 
 use types::*;
 
@@ -50,8 +51,12 @@ pub fn historian_hysteria() {
     // println!("The fixed update mid-queue-sum is {}", fixed_queue_mid_sum);
 
     // Friday 06
-    let (guard_position_count, loop_obstacle_count) =
+    // let (guard_position_count, loop_obstacle_count) =
-        fri_06::guard_gallivant("./assets/day_6_guard_map_input");
+    //     fri_06::guard_gallivant("./assets/day_6_guard_map_input");
-    println!("The guard will visit {} positions", guard_position_count);
+    // println!("The guard will visit {} positions", guard_position_count);
-    println!("The guard would loop on {} positions", loop_obstacle_count);
+    // println!("The guard would loop on {} positions", loop_obstacle_count);
+
+    // Saturday 07
+    let calibration_result = sat_07::bridge_repair("./assets/day_7_calibrations_input");
+    println!("The total calibration result is {}", calibration_result);
 }

src/advent_of_code/sat_07.rs

@@ -0,0 +1,83 @@
+use primes::{PrimeSet, Sieve};
+
+use super::*;
+
+pub fn bridge_repair(input: &str) -> CalibrationResult {
+    let equation_vec = utils::read_calibration_equations(input);
+    let mut sum_result: CalibrationResult = 0;
+
+    for equation in equation_vec {
+        if is_equation_true(&equation) {
+            sum_result += equation.0;
+        }
+    }
+
+    sum_result
+}
+
+pub fn is_equation_true(equation: &Calibration) -> bool {
+    let operation_variants = generate_operation_variants(equation.1.len() as u32 - 1);
+
+    for variant in operation_variants {
+        let mut local_operands = equation.1.clone();
+        local_operands.reverse();
+        let result = calc_operation(local_operands, variant);
+        if result == equation.0 {
+            return true;
+        }
+    }
+
+    false
+}
+
+// FIXME: this goes wrong on large numbers
+pub fn generate_operation_variants(count: u32) -> Vec<Vec<Operation>> {
+    let mut variant_list: Vec<Vec<Operation>> = vec![];
+
+    let mut pset = Sieve::new(); // get prime numbers
+
+    let variant_num = 2i32.pow(count);
+
+    for variant_index in 0..variant_num {
+        let mut new_vec: Vec<Operation> = vec![];
+        for new_operand_index in 0..count {
+            match variant_index as u64 % pset.get(new_operand_index as usize) {
+                0 => new_vec.push(Operation::MUL),
+                _ => new_vec.push(Operation::SUM),
+            }
+        }
+        variant_list.push(new_vec);
+    }
+
+    variant_list
+}
+
+pub fn calc_operation(
+    operands: CalibrationEquation,
+    operators: Vec<Operation>,
+) -> CalibrationResult {
+    if operands.len() == 2 {
+        return operate(&operands[0], &operands[1], &operators[0]);
+    }
+
+    return operate(
+        &operands[0],
+        &calc_operation(operands[1..].to_vec(), operators[1..].to_vec()),
+        &operators[0],
+    );
+}
+
+pub fn operate(
+    first: &CalibrationResult,
+    second: &CalibrationResult,
+    operation: &Operation,
+) -> CalibrationResult {
+    match operation {
+        Operation::SUM => {
+            return first + second;
+        }
+        Operation::MUL => {
+            return first * second;
+        }
+    }
+}

src/advent_of_code/types.rs

@@ -45,3 +45,14 @@ pub struct Guard {
     pub y: usize,
     pub dir: Direction,
 }
+
+// Bridge repair
+pub type CalibrationResult = u128;
+pub type CalibrationEquation = Vec<CalibrationResult>;
+pub struct Calibration(pub CalibrationResult, pub CalibrationEquation);
+
+#[derive(Debug, Clone, Copy)]
+pub enum Operation {
+    SUM,
+    MUL,
+}

src/advent_of_code/utils.rs

@@ -125,6 +125,25 @@ pub fn read_floor_map_and_guard_input(input: &str) -> (Guard, FloorMap) {
     (the_guard, floor_map)
 }
 
+pub fn read_calibration_equations(input: &str) -> Vec<Calibration> {
+    let mut calibration_list: Vec<Calibration> = vec![];
+
+    for line in read_to_string(input).unwrap().lines() {
+        if let Some((test_value, equation_values)) = line.split_once(": ") {
+            let mut values: CalibrationEquation = vec![];
+            for equation_value in equation_values.split(" ") {
+                values.push(equation_value.parse::<CalibrationResult>().unwrap());
+            }
+            calibration_list.push(Calibration(
+                test_value.parse::<CalibrationResult>().unwrap(),
+                values,
+            ));
+        }
+    }
+
+    calibration_list
+}
+
 pub fn calc_distance<T>(num_1: T, num_2: T) -> T
 where
     T: PartialOrd + Sub<Output = T>,