diff --git a/Dockerfile b/Dockerfile
index 22dde96..6c2b000 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -29,7 +29,7 @@ WORKDIR ${WORKDIR}
 
 RUN  apk add --update --no-cache make nodejs npm wget \
   && apk add --update --no-cache yamllint \
-  && npm install -g --ignore-scripts markdownlint-cli
+  && npm install -g --ignore-scripts markdownlint-cli@0.47.0
 
 ADD https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh ${WORKDIR}/
 RUN sh install.sh -b $(go env GOPATH)/bin v2.0.0 \
diff --git a/README.md b/README.md
index ee2c74d..776c874 100644
--- a/README.md
+++ b/README.md
@@ -79,8 +79,8 @@ You can run tests in the following ways:
 installed in your SO.
 - [Install and run with make](#install-and-run-using-make) require runtime tools
 and "make" installed in your SO.
-- [Install and run in Docker](#install-and-running-with-docker-) require Docker and
-docker-compose installed.
+- [Install and run in Docker](#install-and-running-with-docker-) require Docker
+  and docker-compose installed.
 - (⭐️)
 [Install and in Docker with make](#install-and-running-with-docker--using-make)
 require docker-compose and make installed.
diff --git a/docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md b/docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md
index 1e9df62..770a064 100644
--- a/docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md
+++ b/docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md
@@ -49,7 +49,8 @@ The third line contains `n` space-separated strings, each `node[i]`.
 
 - $ 1 \leq m, n \leq 30000 $
 - $ 1 \leq $ length of `magazine[i]` and `note[i]` $ \leq 5 $
-- Each word consists of English alphabetic letters (i.e., `a` to `z` and `A` to `Z`).
+- Each word consists of English alphabetic letters (i.e., `a` to `z` and `A` to
+  `Z`).
 
 ## Sample Input 0
 
diff --git a/docs/hackerrank/interview_preparation_kit/greedy_algorithms/angry-children.md b/docs/hackerrank/interview_preparation_kit/greedy_algorithms/angry-children.md
index 1177d8e..a9d8abd 100644
--- a/docs/hackerrank/interview_preparation_kit/greedy_algorithms/angry-children.md
+++ b/docs/hackerrank/interview_preparation_kit/greedy_algorithms/angry-children.md
@@ -140,4 +140,5 @@ max(1,2,3,4) - min(1,2,3,4) = 4 - 1 = 3
 
 ## Explanation 2
 
-Here `k = 2`. `arr' = [2, 2]` or `arr' = [1, 1]` give the minimum unfairness of `0`.
+Here `k = 2`. `arr' = [2, 2]` or `arr' = [1, 1]` give the minimum unfairness
+of `0`.
diff --git a/docs/hackerrank/interview_preparation_kit/greedy_algorithms/greedy-florist.md b/docs/hackerrank/interview_preparation_kit/greedy_algorithms/greedy-florist.md
index c5d6e78..9b42665 100644
--- a/docs/hackerrank/interview_preparation_kit/greedy_algorithms/greedy-florist.md
+++ b/docs/hackerrank/interview_preparation_kit/greedy_algorithms/greedy-florist.md
@@ -74,7 +74,8 @@ the original price of each flower.
 
 ## Explanation 0
 
-There are `n = 3` flowers with costs `c = [2, 5, ,6]` and `k = 3` people in the group.
+There are `n = 3` flowers with costs `c = [2, 5, ,6]` and `k = 3` people
+in the group.
 If each person buys one flower,
 the total cost of prices paid is `2 + 5 + 6 = 13` dollars.
 Thus, we print `13` as our answer.
diff --git a/docs/projecteuler/problem0002.md b/docs/projecteuler/problem0002.md
index 34abbf2..4ba89bf 100644
--- a/docs/projecteuler/problem0002.md
+++ b/docs/projecteuler/problem0002.md
@@ -1,6 +1,7 @@
 # [Even Fibonacci numbers](https://projecteuler.net/problem=2)
 
-Each new term in the Fibonacci sequence is generated by adding the previous two terms.
+Each new term in the Fibonacci sequence is generated by adding the previous
+two terms.
 By starting with 1 and 2, the first 10 terms will be:
 
 $ 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... $
diff --git a/docs/projecteuler/problem0020.md b/docs/projecteuler/problem0020.md
index 5c1e200..1eff679 100644
--- a/docs/projecteuler/problem0020.md
+++ b/docs/projecteuler/problem0020.md
@@ -3,6 +3,7 @@
 $ n! $ means $ n × (n − 1) × ... × 3 × 2 × 1 $
 
 For example, $ 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800 $,
-and the sum of the digits in the number $ 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27 $.
+and the sum of the digits in the number $ 10! $ is
+$ 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27 $.
 
 Find the sum of the digits in the number $ 100! $