Merge pull request #82 from BrianLusina/feat/jump-game

Puzzles | Arrays - jump game

DIRECTORY.md

@@ -162,6 +162,7 @@
     * Singly Linked List
       * [Node](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/singly_linked_list/node.py)
       * [Test Singly Linked List](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/singly_linked_list/test_singly_linked_list.py)
+      * [Test Singly Linked List Pairwise Swap](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/singly_linked_list/test_singly_linked_list_pairwise_swap.py)
       * [Test Singly Linked List Rotate](https://github.com/BrianLusina/PythonSnips/blob/master/datastructures/linked_lists/singly_linked_list/test_singly_linked_list_rotate.py)
   * Lists
     * Bus Stops
@@ -358,6 +359,8 @@
       * [Test Container With Most Water](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/container_with_most_water/test_container_with_most_water.py)
     * Increasing Triplet Subsequence
       * [Test Increasing Triplet](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/increasing_triplet_subsequence/test_increasing_triplet.py)
+    * Jump Game
+      * [Test Jump Game](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/jump_game/test_jump_game.py)
     * Kid With Greatest No Of Candies
       * [Test Kids With Greatest Candies](https://github.com/BrianLusina/PythonSnips/blob/master/puzzles/arrays/kid_with_greatest_no_of_candies/test_kids_with_greatest_candies.py)
     * Longest Increasing Subsequence

puzzles/arrays/jump_game/README.md

@@ -0,0 +1,29 @@
+# Jump Game
+
+You are given an integer array nums. You are initially positioned at the array's first index, and each element in the
+array represents your maximum jump length at that position.
+
+Return true if you can reach the last index, or false otherwise.
+
+```text
+Example 1:
+
+Input: nums = [2,3,1,1,4]
+Output: true
+Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index.
+```
+
+```text
+Example 2:
+
+Input: nums = [3,2,1,0,4]
+Output: false
+Explanation: You will always arrive at index 3 no matter what. Its maximum jump length is 0, which makes it impossible
+to reach the last index.
+```
+
+## Topics
+
+- Array
+- Dynamic Programming
+- Greedy

puzzles/arrays/jump_game/__init__.py

@@ -0,0 +1,15 @@
+from typing import List
+
+
+def can_jump(nums: List[int]) -> bool:
+    current_position = nums[0]
+
+    for idx in range(1, len(nums)):
+        if current_position == 0:
+            return False
+
+        current_position -= 1
+
+        current_position = max(current_position, nums[idx])
+
+    return True

puzzles/arrays/jump_game/test_jump_game.py

@@ -0,0 +1,21 @@
+import unittest
+
+from . import can_jump
+
+
+class CanJumpTestCase(unittest.TestCase):
+    def test_1(self):
+        """nums = [2,3,1,1,4] should return true"""
+        nums = [2, 3, 1, 1, 4]
+        actual = can_jump(nums)
+        self.assertTrue(actual)
+
+    def test_2(self):
+        """nums = [3,2,1,0,4] should return false"""
+        nums = [3, 2, 1, 0, 4]
+        actual = can_jump(nums)
+        self.assertFalse(actual)
+
+
+if __name__ == '__main__':
+    unittest.main()