Break day 7 into modules

day_07/src/equation/operator_set.rs

@@ -0,0 +1,26 @@
+use std::collections::HashSet;
+
+fn create_operator_set_recurse(
+    operators_permutation_set: &mut HashSet<Vec<bool>>,
+    operators: Vec<bool>,
+) {
+    operators_permutation_set.insert(operators.clone());
+    if !operators.contains(&false) {
+        return;
+    }
+
+    for i in 0..operators.len() {
+        if operators[i] {
+            continue;
+        }
+        let mut new_operators = operators.clone();
+        new_operators[i] = true;
+        create_operator_set_recurse(operators_permutation_set, new_operators);
+    }
+}
+
+pub fn create_operator_set(num_of_operators: usize) -> HashSet<Vec<bool>> {
+    let mut operator_sets: HashSet<Vec<bool>> = HashSet::new();
+    create_operator_set_recurse(&mut operator_sets, vec![false; num_of_operators]);
+    operator_sets
+}