From feb122711a1092d7035c07198698aa45c85d97e0 Mon Sep 17 00:00:00 2001
From: Daniel Heras Quesada <dani.heras@hotmail.com>
Date: Sun, 23 Nov 2025 23:15:49 +0100
Subject: [PATCH] feat: find_missing

---
 src/modules/exercises/essentials.py | 11 +++++++++++
 tests/test_essentials.py            | 10 +++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/modules/exercises/essentials.py b/src/modules/exercises/essentials.py
index b3039e3..2cff5ea 100644
--- a/src/modules/exercises/essentials.py
+++ b/src/modules/exercises/essentials.py
@@ -9,3 +9,14 @@ def maximum_subarray_sum(input_array: list[int]):
 				max_sum = temp_sum
 				subarray = temp_subarray
 	return [max_sum, subarray]
+
+def get_array_range(min, max):
+	arr = []
+	for n in range(min, max + 1):
+		arr.append(n)
+	return arr
+
+def find_missing(input_aray: list[int]):
+	return sum(get_array_range(1, len(input_aray) + 1)) - sum(input_aray)
+
+def trap_rain_water(input_aray: list[int]):
diff --git a/tests/test_essentials.py b/tests/test_essentials.py
index 13345e4..0b80fb8 100644
--- a/tests/test_essentials.py
+++ b/tests/test_essentials.py
@@ -16,4 +16,12 @@ def test_subarray_sum():
 	expected = [25, [5,4,1,7,8]]
 	assert result == expected
 
-
+def test_find_missing():
+	input = [8,2,4,5,3,7,1]
+	result = find_missing(input)
+	expected = 6
+	assert result == expected
+	input = [1,2,3,5]
+	result = find_missing(input)
+	expected = 4
+	assert result == expected