Add README and solution for day4

2019-12-07 12:53:43 +01:00
parent ffbe0f66a1
commit 40e0caa31a
4 changed files with 67 additions and 0 deletions
@@ -0,0 +1,18 @@
+use itertools::Itertools;
+
+fn main() {
+    let passwords = (152_086_usize..670_282_usize)
+        .map(|x| x.to_string().chars().collect::<Vec<char>>())
+        .filter(|x| x.iter().zip(x.iter().skip(1)).all(|(x,y)| x <= y))
+        .filter(|x| {
+            for (_,g) in &x.iter().group_by(|&y| y) {
+                if g.count() == 2 {
+                    return true;
+                }
+            }
+            false
+        })
+    .count();
+
+    println!("Solution: {:?}", passwords);
+}