Merge pull request #88 from BrianLusina/feat/two-sum

Algorithms | Arrays - Two sum

DIRECTORY.md

@@ -9,6 +9,8 @@
       * [Test Remove Duplicates](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/arrays/remove_duplicates/test_remove_duplicates.py)
     * Remove Element
       * [Test Remove Element](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/arrays/remove_element/test_remove_element.py)
+    * Two Sum
+      * [Test Two Sum](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/arrays/two_sum/test_two_sum.py)
   * Backtracking
     * Combination
       * [Test Combination 2](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/backtracking/combination/test_combination_2.py)
@@ -373,6 +375,8 @@
       * [Test Array 3 Pointers](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/array_3_pointers/test_array_3_pointers.py)
     * Can Place Flowers
       * [Test Can Place Flowers](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/can_place_flowers/test_can_place_flowers.py)
+    * Candy
+      * [Test Candy](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/candy/test_candy.py)
     * Container With Most Water
       * [Test Container With Most Water](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/container_with_most_water/test_container_with_most_water.py)
     * Gas Stations
@@ -568,6 +572,8 @@
     * [Test Mini Max Sum](https://github.com/BrianLusina/PythonSnips/blob/master/pymath/mini_max_sum/test_mini_max_sum.py)
   * Multiply 5
     * [Test Multiply 5](https://github.com/BrianLusina/PythonSnips/blob/master/pymath/multiply_5/test_multiply_5.py)
+  * Pascals Triangle
+    * [Test Pascals Triangle](https://github.com/BrianLusina/PythonSnips/blob/master/pymath/pascals_triangle/test_pascals_triangle.py)
   * Perfect Square
     * [Test Perfect Squares](https://github.com/BrianLusina/PythonSnips/blob/master/pymath/perfect_square/test_perfect_squares.py)
   * Super Size
@@ -593,6 +599,8 @@
     * [Test Balanced Paren](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/balanced_paren/test_balanced_paren.py)
   * Domain Name
     * [Extract Host](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/domain_name/extract_host.py)
+  * First Occurrence
+    * [Test First Occurrence](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/first_occurrence/test_first_occurrence.py)
   * Greatest Common Divisor
     * [Test Greatest Common Divisor](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/greatest_common_divisor/test_greatest_common_divisor.py)
   * Issubsequence
@@ -625,6 +633,8 @@
     * [Test Reverse Words](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/reverse_words/test_reverse_words.py)
   * String Compression
     * [Test String Compression](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/string_compression/test_string_compression.py)
+  * Text Justification
+    * [Test Text Justification](https://github.com/BrianLusina/PythonSnips/blob/master/pystrings/text_justification/test_text_justification.py)
 
 ## Reactivex
   * [Concurrency](https://github.com/BrianLusina/PythonSnips/blob/master/reactivex/concurrency.py)
@@ -986,6 +996,8 @@
     * [String1](https://github.com/BrianLusina/PythonSnips/blob/master/utils/basic/string1.py)
     * [String2](https://github.com/BrianLusina/PythonSnips/blob/master/utils/basic/string2.py)
     * [Wordcount](https://github.com/BrianLusina/PythonSnips/blob/master/utils/basic/wordcount.py)
+  * Benchmark
+    * [Timer](https://github.com/BrianLusina/PythonSnips/blob/master/utils/benchmark/timer.py)
   * Context Mgrs
     * [Array Init Test](https://github.com/BrianLusina/PythonSnips/blob/master/utils/context_mgrs/array_init_test.py)
     * [Perf Timer](https://github.com/BrianLusina/PythonSnips/blob/master/utils/context_mgrs/perf_timer.py)

algorithms/arrays/two_sum/README.md

@@ -0,0 +1,42 @@
+# Two Sum - Input Array Is Sorted
+
+Given a 1-indexed array of integers numbers that is already sorted in non-decreasing order, find two numbers such that
+they add up to a specific target number. Let these two numbers be numbers[index1] and numbers[index2] where 1 <=
+index1 < index2 <= numbers.length.
+
+Return the indices of the two numbers, index1 and index2, added by one as an integer array [index1, index2] of length 2.
+
+The tests are generated such that there is exactly one solution. You may not use the same element twice.
+
+Your solution must use only constant extra space.
+
+```text
+
+Example 1:
+
+Input: numbers = [2,7,11,15], target = 9
+Output: [1,2]
+Explanation: The sum of 2 and 7 is 9. Therefore, index1 = 1, index2 = 2. We return [1, 2].
+```
+
+```text
+Example 2:
+
+Input: numbers = [2,3,4], target = 6
+Output: [1,3]
+Explanation: The sum of 2 and 4 is 6. Therefore index1 = 1, index2 = 3. We return [1, 3].
+```
+
+```text
+Example 3:
+
+Input: numbers = [-1,0], target = -1
+Output: [1,2]
+Explanation: The sum of -1 and 0 is -1. Therefore index1 = 1, index2 = 2. We return [1, 2].
+```
+
+## Related Topics
+
+- Array
+- Two Pointers
+- Binary Search

algorithms/arrays/two_sum/__init__.py

@@ -0,0 +1,12 @@
+from typing import List
+
+
+def two_sum(numbers: List[int], target: int) -> List[int]:
+    m = {}
+
+    for idx, num in enumerate(numbers, start=1):
+        complement = target - num
+
+        if complement in m:
+            return [m[complement], idx]
+        m[num] = idx

algorithms/arrays/two_sum/test_two_sum.py

@@ -0,0 +1,32 @@
+import unittest
+from . import two_sum
+
+
+class TwoSumTestCase(unittest.TestCase):
+    def test_1(self):
+        """numbers = [2,7,11,15], target = 9"""
+        numbers = [2, 7, 11, 15]
+        target = 9
+        expected = [1, 2]
+        actual = two_sum(numbers, target)
+        self.assertEqual(expected, actual)
+
+    def test_2(self):
+        """numbers = [2,3,4], target = 6"""
+        numbers = [2, 3, 4]
+        target = 6
+        expected = [1, 3]
+        actual = two_sum(numbers, target)
+        self.assertEqual(expected, actual)
+
+    def test_3(self):
+        """numbers = [-1,0], target = -1"""
+        numbers = [-1, 0]
+        target = -1
+        expected = [1, 2]
+        actual = two_sum(numbers, target)
+        self.assertEqual(expected, actual)
+
+
+if __name__ == '__main__':
+    unittest.main()