diff --git a/Cargo.lock b/Cargo.lock
index fec8700..c6db471 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3,4 +3,23 @@
 [[package]]
 name = "aoc_2019"
 version = "0.1.0"
+dependencies = [
+ "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
 
+[[package]]
+name = "either"
+version = "1.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "itertools"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[metadata]
+"checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
+"checksum itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f56a2d0bc861f9165be4eb3442afd3c236d8a98afd426f65d92324ae1091a484"
diff --git a/Cargo.toml b/Cargo.toml
index 07bd15b..99c314c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+itertools = "0.8.2"
diff --git a/src/tasks/day04.rs b/src/tasks/day04.rs
index c9aa457..c155cab 100644
--- a/src/tasks/day04.rs
+++ b/src/tasks/day04.rs
@@ -1,3 +1,4 @@
+use itertools::Itertools;
 use std::ops::RangeInclusive;
 
 pub fn run() {
@@ -10,8 +11,8 @@ fn task1(range: &RangeInclusive<i32>) {
     let count = range
         .clone()
         .map(|v| format!("{}", v))
-        .filter(|s| s.chars().zip(s.chars().skip(1)).any(|(a, b)| a == b))
-        .filter(|s| s.chars().zip(s.chars().skip(1)).all(|(a, b)| a <= b))
+        .filter(|s| s.chars().tuple_windows().any(|(a, b)| a == b))
+        .filter(|s| s.chars().tuple_windows().all(|(a, b)| a <= b))
         .count();
 
     println!("Task 1: There are {} valid passwords in the range", count);
@@ -23,11 +24,11 @@ fn task2(range: &RangeInclusive<i32>) {
         .map(|v| format!("{}", v))
         .filter(|s| {
             let s = format!("0{}0", s);
-            (0..5)
-                .map(|i| s[i..i + 4].chars().collect::<Vec<_>>())
-                .any(|sub| sub[0] != sub[1] && sub[1] == sub[2] && sub[2] != sub[3])
+            s.chars()
+                .tuple_windows()
+                .any(|(a, b, c, d)| a != b && b == c && c != d)
         })
-        .filter(|s| s.chars().zip(s.chars().skip(1)).all(|(a, b)| a <= b))
+        .filter(|s| s.chars().tuple_windows().all(|(a, b)| a <= b))
         .count();
 
     println!("Task 1: There are {} valid passwords in the range", count);