Working on day 7

crates/day_7/src/equation.rs

@@ -8,10 +8,12 @@
 ******************************************************************************/
 
 #[derive(Copy, Clone, PartialEq, Debug)]
-pub enum Operators
+pub enum Operator
 {
 	Add,
 	Mult,
+
+	NumOperators,
 }
 
 #[derive(Clone, Debug)]
@@ -45,6 +47,7 @@ impl Equation
 			values.push(v.parse::<i64>().expect(&format!("ERROR: Failed to parse value: {}", v)));
 		}
 
+
 		Equation { values, result }
 	}
 
@@ -59,12 +62,42 @@ impl Equation
 		println!();
 	}
 
-	// Returns None if the equation can not be made true
+	// Returns: valid order of operations, or None if the equation can not be valid
 	// NOTE: Operators are always evaluated left-to-right, not according to precedence rules!
-	pub fn can_be_true(self: &Equation) -> Option<Vec<Operators>>
+	pub fn validate(self: &Equation) -> Option<Vec<Operator>>
 	{
-		
+
+		let mut operators = vec![Operator::Add; self.values.len() - 1];
+		let num_oper_permutations =  (Operator::NumOperators as i32).pow(operators.len() as u32); 
+
+		for oper_mask in 0..num_oper_permutations
+		{
+			for i in 0..operators.len()
+			{
+				operators[i] = match oper_mask & (1 << i) == 0
+				{
+					true => Operator::Add,
+					false => Operator::Mult,
+				};
+			}
+
+			// TODO: Test operator sequence
+		}
 
 		None
 	}
+
+	pub fn oper_sequence_is_valid(self: &Equation, opers: &Vec<Operator>) -> bool
+	{
+		// let actual_result = 0;
+		// for oper in opers
+		// {
+		// 	match oper
+		// 	{
+		// 		Operator::Add =>
+		// 	}
+		// }
+
+		false
+	}
 }