day2 solution 2

1 files changed, 21 insertions, 7 deletions

diff --git a/src/bin/day2.rs b/src/bin/day2.rs
index e34b8b0..3d66a45 100644
--- a/src/bin/day2.rs
+++ b/src/bin/day2.rs
@@ -2,8 +2,8 @@ static DAY: u8 = 2;
 
 fn main() {
     let input = advent::read_lines(DAY);
-    println!("{DAY}a: {}", safe_reports(&input));
-    println!("{DAY}b: {}", 0);
+    println!("{DAY}a: {}", safe_reports(&input, false));
+    println!("{DAY}b: {}", safe_reports(&input, true));
 }
 
 fn is_report_safe(report: &[i32]) -> bool {
@@ -20,7 +20,7 @@ fn is_report_safe(report: &[i32]) -> bool {
     true
 }
 
-fn safe_reports(input: &[String]) -> usize {
+fn safe_reports(input: &[String], with_dampener: bool) -> usize {
     let mut reports = Vec::new();
     for line in input {
         let numbers = line.split(" ")
@@ -28,9 +28,22 @@ fn safe_reports(input: &[String]) -> usize {
                           .collect::<Vec<_>>();
         reports.push(numbers);
     }
-    reports.iter()
-           .filter(|x| is_report_safe(x))
-           .count()
+    let mut count = 0;
+    for report in reports {
+        if is_report_safe(&report) {
+            count += 1;
+        } else if with_dampener {
+            for i in 0 .. report.len() {
+                let mut dampened = report.clone();
+                dampened.remove(i);
+                if is_report_safe(&dampened) {
+                    count += 1;
+                    break;
+                }
+            }
+        }
+    }
+    count
 }
 
 #[cfg(test)]
@@ -47,6 +60,7 @@ mod tests {
             "8 6 4 4 1",
             "1 3 6 7 9",
         ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
-        assert_eq!(safe_reports(&input), 2);
+        assert_eq!(safe_reports(&input, false), 2);
+        assert_eq!(safe_reports(&input, true), 4);
     }
 }