Day 6 - Some cleanup

src/day6/main.rs

@@ -2,8 +2,18 @@ use anyhow::Result;
 use std::fs;
 
 enum Op {
-    Sum,
-    Mult,
+    Sum = '+' as isize,
+    Mult = '*' as isize,
+}
+
+impl Into<Op> for char {
+    fn into(self) -> Op {
+        match self {
+            '*' => Op::Mult,
+            '+' => Op::Sum,
+            _ => panic!("invalid char"),
+        }
+    }
 }
 
 struct Ans {
@@ -12,56 +22,61 @@ struct Ans {
     op: Option<Op>,
 }
 
+impl Ans {
+    fn new(mult: u64, sum: u64) -> Ans {
+        Ans {
+            op: None,
+            mult,
+            sum,
+        }
+    }
+
+    fn extend(&mut self, num: u64) {
+        self.mult *= num;
+        self.sum += num;
+    }
+
+    fn res(&self) -> u64 {
+        match self.op {
+            Some(Op::Sum) => self.sum,
+            Some(Op::Mult) => self.mult,
+            _ => panic!("you are doing something wrong"),
+        }
+    }
+}
+
 fn sol2(text: &str) -> Result<()> {
     let lines = text.split("\n").collect::<Vec<&str>>();
     // There is an empty line at the end
     let lines_len = lines.len() - 1;
-    let row_size = lines[0].len();
 
     let mut grand_total = 0;
-
-    let mut cur_ans = Ans {
-        op: None,
-        mult: 1,
-        sum: 0,
-    };
-    for x in (0..=row_size).rev() {
+    let mut cur_ans = Ans::new(1, 0);
+    let mut x: i64 = lines[0].len() as i64 + 1;
+    while x >= 0 {
         // Note if we have found a no space char
         let mut cur_num = 0;
         let mut has_found = false;
         let mut has_commited = false;
         for y in 0..lines_len {
-            let c = lines[y].chars().nth(x).unwrap_or(' ');
+            let c = lines[y].chars().nth(x as usize).unwrap_or(' ');
             match c {
                 ' ' => {
-                    if has_found {
-                        if !has_commited {
-                            has_commited = true;
-                            // We have reached the end of the colum
-                            cur_ans.mult *= cur_num;
-                            cur_ans.sum += cur_num;
-                        }
+                    if has_found && !has_commited {
+                        // We have reached the end of the colum
+                        has_commited = true;
+                        cur_ans.extend(cur_num);
                     }
                 }
-                '*' => {
-                    if !has_found {
-                        panic!("unrechable")
-                    }
-                    if has_commited {
-                        grand_total += cur_ans.mult;
-                    } else {
-                        grand_total += cur_ans.mult * cur_num;
-                    }
-                }
-                '+' => {
-                    if !has_found {
-                        panic!("unrechable")
-                    }
-                    if has_commited {
-                        grand_total += cur_ans.sum;
-                    } else {
-                        grand_total += cur_ans.sum + cur_num;
+                '*' | '+' => {
+                    assert!(has_found);
+                    if !has_commited {
+                        cur_ans.extend(cur_num);
                     }
+                    cur_ans.op = Some(c.into());
+                    grand_total += cur_ans.res();
+                    cur_ans = Ans::new(1, 0);
+                    x -= 1;
                 }
                 c => {
                     // convert ascci to int
@@ -71,14 +86,7 @@ fn sol2(text: &str) -> Result<()> {
                 }
             }
         }
-        // An empty col we reset ans
-        if !has_found {
-            cur_ans = Ans {
-                op: None,
-                mult: 1,
-                sum: 0,
-            };
-        }
+        x -= 1;
     }
 
     println!("sol2: {}", grand_total);
@@ -99,38 +107,18 @@ fn main() -> Result<()> {
                 .fold(probs, |mut probs, (i, op)| {
                     if probs.len() <= i {
                         let as_num: u64 = op.parse().unwrap();
-                        probs.push(Ans {
-                            sum: as_num,
-                            mult: as_num,
-                            op: None,
-                        });
-                        probs
+                        probs.push(Ans::new(as_num, as_num));
                     } else {
                         match op {
-                            "+" => {
-                                probs[i].op = Some(Op::Sum);
-                            }
-                            "*" => {
-                                probs[i].op = Some(Op::Mult);
-                            }
-                            _ => {
-                                let as_num: u64 = op.parse().unwrap();
-                                probs[i].sum += as_num;
-                                probs[i].mult *= as_num;
-                            }
+                            "+" | "*" => probs[i].op = Some(op.chars().nth(0).unwrap().into()),
+                            _ => probs[i].extend(op.parse().unwrap()),
                         }
-                        probs
                     }
+                    probs
                 })
         });
 
-    let sol1 = problems.iter().fold(0, |s, i| {
-        s + match i.op {
-            Some(Op::Sum) => i.sum,
-            Some(Op::Mult) => i.mult,
-            None => panic!("unreachable"),
-        }
-    });
+    let sol1 = problems.iter().fold(0, |s, i| s + i.res());
 
     println!("sol1: {}!", sol1);