From b32d0465ea81ca81a09e2524c4f39ce41208978e Mon Sep 17 00:00:00 2001
From: boyska <piuttosto@logorroici.org>
Date: Tue, 19 May 2020 11:28:30 +0200
Subject: [PATCH] small (but useful) optimization to is_anagram

checking length avoids sorting in many cases
---
 src/main.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 13dac1d..9464066 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -90,7 +90,16 @@ fn sort_word(word: &str) -> Result<String, impl std::error::Error> {
 fn is_anagram(word: &str) -> impl std::ops::FnMut(&&String) -> bool {
     // filtro
     let sorted_word = sort_word(line_to_word(word).as_str()).unwrap();
-    move |w| sorted_word == sort_word(w.as_str()).unwrap()
+    move |w| {
+        if sorted_word.len() != w.len() {
+            // this check doesn't add any correctness to the algorithm, but
+            // is a small optimization: avoids sorting w if the length is different
+            false
+        } else {
+            let sorted_other = sort_word(w.as_str()).unwrap();
+            sorted_word == sorted_other
+        }
+    }
 }
 
 // filtri }}}