diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9aefdb2..7b39dac 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -53,3 +53,8 @@ day-10:
   stage: build
   script:
     - cd day10; cargo run --release ./input
+
+day-11:
+  stage: build
+  script:
+    - cd day11; cargo run --release ./input
diff --git a/day11/Cargo.toml b/day11/Cargo.toml
new file mode 100644
index 0000000..8f5b9a5
--- /dev/null
+++ b/day11/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "day11"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/day11/input b/day11/input
new file mode 100644
index 0000000..209742f
--- /dev/null
+++ b/day11/input
@@ -0,0 +1,10 @@
+4871252763
+8533428173
+7182186813
+2128441541
+3722272272
+8751683443
+3135571153
+5816321572
+2651347271
+7788154252
diff --git a/day11/src/main.rs b/day11/src/main.rs
new file mode 100644
index 0000000..a17a469
--- /dev/null
+++ b/day11/src/main.rs
@@ -0,0 +1,89 @@
+use std::{fs, env, vec};
+
+fn read_input(path: &str) -> String {
+    return fs::read_to_string(path).expect("Cannot read file.");
+}
+
+fn parse_input(s: &str) -> Vec<Vec<u32>> {
+    return s.lines()
+        .map(|l| l.chars().filter_map(|e| e.to_digit(10)).collect())
+        .collect();
+}
+
+fn compute_octopus(v: &mut Vec<Vec<u32>>, l: usize, c: usize, f: &mut Vec<(usize, usize)>) {
+    v[l][c] += 1;
+    if v[l][c] > 9 && !f.contains(&(l, c)) {
+        f.push((l, c));
+        flash_around(v, l, c, f);
+    }
+}
+
+fn flash_around(v: &mut Vec<Vec<u32>>, l: usize, c: usize, f: &mut Vec<(usize, usize)>) {
+    for i in (l as i32 - 1)..=(l as i32 + 1) {
+        for j in (c as i32 - 1)..=(c as i32 + 1) {
+            let x = i as usize;
+            let y = j as usize;
+            if i >= 0 && x < v.len()
+                && j >= 0 && y < v[x].len() {
+                compute_octopus(v, x, y, f);
+            }
+        }
+    }
+}
+
+fn apply_one_day(v: &mut Vec<Vec<u32>>) -> u32 {
+    let mut f = vec![];
+    for l in 0..v.len() {
+        for c in 0..v[l].len() {
+            compute_octopus(v, l, c, &mut f);
+        }
+    }
+    for l in 0..v.len() {
+        for c in 0..v[l].len() {
+            if v[l][c] > 9 {
+                v[l][c] = 0;
+            }
+        }
+    }
+    return f.len() as u32;
+}
+
+fn apply_x_days(mut v: Vec<Vec<u32>>, x: u32) -> u32 {
+    let mut n = 0;
+    for _i in 0..x {
+        n += apply_one_day(&mut v);
+    }
+    return n;
+}
+
+fn is_uniform(v: &Vec<Vec<u32>>) -> bool {
+    if v.is_empty() || v[0].is_empty() { return true; }
+    let x = v[0][0];
+    for l in v {
+        for i in l {
+            if *i != x { return false; }
+        }
+    }
+    return true;
+}
+
+fn apply_while_not_synced(mut v: Vec<Vec<u32>>) -> u32 {
+    let mut i = 0;
+    while !is_uniform(&v) {
+        apply_one_day(&mut v);
+        i += 1;
+    }
+    return i;
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    for arg in args.iter().skip(1) {
+        let input = read_input(&arg);
+        let vec_in = parse_input(&input);
+        println!("[{}]", &arg);
+        println!("\t[Part 1] => Answer is '{}'.", apply_x_days(vec_in.clone(), 100));
+        println!("\t[Part 2] => Answer is '{}'.", apply_while_not_synced(vec_in));
+    }
+}
+