Day 4: passphrase anagrams

1 files changed, 37 insertions, 0 deletions

diff --git a/src/bin/day_4.rs b/src/bin/day_4.rs
new file mode 100644
index 0000000..a9a098a
--- /dev/null
+++ b/src/bin/day_4.rs
@@ -0,0 +1,37 @@
+extern crate advent_of_code_2017;
+use advent_of_code_2017::*;
+
+fn main() {
+    let args = AdventArgs::init();
+
+    let valid_count = args.input.iter()
+        .map(|line| {
+            let words = line.split_whitespace().map(|x| x.to_string()).collect::<Vec<String>>();
+            if args.part == 1 {
+                let mut deduped_words = words.clone();
+                deduped_words.sort();
+                deduped_words.dedup();
+                words.len() == deduped_words.len()
+            } else {
+                !words.iter().enumerate().any(|(i, word1)| {
+                    words.iter().enumerate().any(|(j, word2)| {
+                        i != j && is_anagram(word1, word2)
+                    })
+                })
+            }
+        })
+        .filter(|&valid| valid)
+        .count();
+
+    println!("Valid count: {}", valid_count);
+}
+
+fn is_anagram(word1: &str, word2: &str) -> bool {
+    let mut chars1 = word1.chars().collect::<Vec<_>>();
+    chars1.sort();
+    let mut chars2 = word2.chars().collect::<Vec<_>>();
+    chars2.sort();
+
+    chars1.len() == chars2.len() &&
+        chars1.iter().zip(chars2.iter()).all(|(c1, c2)| c1 == c2)
+}