From 732fab4395de7a4965fcd380c0cebfd241683464 Mon Sep 17 00:00:00 2001
From: Luiz Felipe Limao <limao@limao.com>
Date: Sat, 25 Jun 2022 19:15:58 -0300
Subject: [PATCH] feature: add balanced brackets

---
 README.md                       |  3 ++-
 stack/balanced_brackets.go      | 23 +++++++++++++++++++++++
 stack/balanced_brackets_test.go | 15 +++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 stack/balanced_brackets.go
 create mode 100644 stack/balanced_brackets_test.go

diff --git a/README.md b/README.md
index cbca464..59d6d01 100644
--- a/README.md
+++ b/README.md
@@ -44,13 +44,14 @@ Algorithms
   * [binary tree](https://en.wikipedia.org/wiki/Binary_search_tree)
   * [stack](https://en.wikipedia.org/wiki/Stack_(abstract_data_type))
   * [queue](https://en.wikipedia.org/wiki/Queue_(abstract_data_type))
+  * [balanced_brackets](https://www.geeksforgeeks.org/check-for-balanced-parentheses-in-an-expression/)
+
 
 #### Numerical
 
   * [gcd](https://en.wikipedia.org/wiki/Greatest_common_divisor)
   * [factorial](https://en.wikipedia.org/wiki/Factorial)
   * [fibonacci](https://en.wikipedia.org/wiki/Fibonacci_number)
-
 Contribution
 ------------
 
diff --git a/stack/balanced_brackets.go b/stack/balanced_brackets.go
new file mode 100644
index 0000000..723872f
--- /dev/null
+++ b/stack/balanced_brackets.go
@@ -0,0 +1,23 @@
+package stack
+
+func isExpressionBalanced(text string) bool {
+	stack := make([]string, 0, len(text))
+
+	for i, char := range text {
+		if char == '(' {
+			stack = append(stack, string(char))
+		}
+		if char == ')' {
+			stack = remove(stack, i-1)
+		}
+	}
+
+	return len(stack) == 0
+}
+
+func remove(s []string, index int) []string {
+	if index >= len(s) {
+		return nil
+	}
+	return append(s[:index], s[index+1:]...)
+}
diff --git a/stack/balanced_brackets_test.go b/stack/balanced_brackets_test.go
new file mode 100644
index 0000000..7da7f2b
--- /dev/null
+++ b/stack/balanced_brackets_test.go
@@ -0,0 +1,15 @@
+package stack
+
+import "testing"
+
+func Test_isExpressionBalanced(t *testing.T) {
+
+	if !isExpressionBalanced("(())") {
+		t.Error("[Error] Expression Balanced is wrong")
+	}
+
+	if isExpressionBalanced("(()") {
+		t.Error("[Error] Expression Balanced is wrong")
+	}
+
+}