1732. Find the Highest Altitude

Author: remy727

README.md

@@ -175,6 +175,7 @@
 | 1680 | Concatenation of Consecutive Binary Numbers | [Ruby](./algorithms/ruby/1680-concatenation-of-consecutive-binary-numbers.rb) | Medium |
 | 1697 | Checking Existence of Edge Length Limited Paths | [Ruby](./algorithms/ruby/1697-checking-existence-of-edge-length-limited-paths.rb) | Hard |
 | 1706 | Where Will the Ball Fall | [Ruby](./algorithms/ruby/1706-where-will-the-ball-fall.rb) | Medium |
+| 1732 | Find the Highest Altitude | [Ruby](./algorithms/ruby/1732-find-the-highest-altitude.rb) | Easy |
 | 1768 | Merge Strings Alternately | [Ruby](./algorithms/ruby/1768-merge-strings-alternately.rb) | Easy |
 | 1822 | Sign of the Product of an Array | [Ruby](./algorithms/ruby/1822-sign-of-the-product-of-an-array.rb) | Easy |
 | 1857 | Largest Color Value in a Directed Graph | [Ruby](./algorithms/ruby/1857-largest-color-value-in-a-directed-graph.rb) | Hard |

algorithms/ruby/0724-find-pivot-index.rb

@@ -2,9 +2,9 @@
 
 # 724. Find Pivot Index
 # https://leetcode.com/problems/find-pivot-index
+# Easy
 
 =begin
-
 Given an array of integers nums, calculate the pivot index of this array.
 
 The pivot index is the index where the sum of all the numbers strictly to the left of the index is equal to the sum of all the numbers strictly to the index's right.
@@ -38,7 +38,6 @@
 ### Constraints:
 * 1 <= nums.length <= 104
 * -1000 <= nums[i] <= 1000
-
 =end
 
 # Runtime 109 ms

algorithms/ruby/1732-find-the-highest-altitude.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+# 1732. Find the Highest Altitude
+# https://leetcode.com/problems/find-the-highest-altitude
+# Easy
+
+=begin
+There is a biker going on a road trip. The road trip consists of n + 1 points at different altitudes. The biker starts his trip on point 0 with altitude equal 0.
+
+You are given an integer array gain of length n where gain[i] is the net gain in altitude between points i and i + 1 for all (0 <= i < n). Return the highest altitude of a point.
+
+Example 1:
+Input: gain = [-5,1,5,0,-7]
+Output: 1
+Explanation: The altitudes are [0,-5,-4,1,1,-6]. The highest is 1.
+
+Example 2:
+Input: gain = [-4,-3,-2,-1,4,3,2]
+Output: 0
+Explanation: The altitudes are [0,-4,-7,-9,-10,-6,-3,-1]. The highest is 0.
+
+Constraints:
+n == gain.length
+1 <= n <= 100
+-100 <= gain[i] <= 100
+=end
+
+# @param {Integer[]} gain
+# @return {Integer}
+def largest_altitude(gain)
+  prefix = gain.inject([]) { |acc, value| acc << acc.last.to_i + value.to_i }
+  max_gain = prefix.max
+  max_gain < 0 ? 0 : max_gain
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_largest_altitude < Test::Unit::TestCase
+  def test_
+    assert_equal 1, largest_altitude([-5, 1, 5, 0, -7])
+    assert_equal 0, largest_altitude([-4, -3, -2, -1, 4, 3, 2])
+  end
+end