feat: Add Ruby code - chapter "Searching" (#1262)

* create RUBY searching files & finish two_sum.rb

* finish linear_search.rb

* finish hashing_search.rb

* finish binary_search.rb

* finish binary_search_insertion.rb

* finish binary_search_edge.rb

* fix: change 'or' to '||'

* fix: Adjust the code style(ruby searching)

* fix: repair file name

* fix: Adjust the output format

* fix: fix 0...nums.length & delete useless require & change into __FILE__==0 block

codes/ruby/chapter_searching/binary_search_edge.rb

@@ -0,0 +1,47 @@
+=begin
+File: binary_search_edge.rb
+Created Time: 2024-04-09
+Author: Blue Bean (lonnnnnnner@gmail.com)
+=end
+
+require_relative './binary_search_insertion'
+
+### 二分查找最左一个 target ###
+def binary_search_left_edge(nums, target)
+  # 等价于查找 target 的插入点
+  i = binary_search_insertion(nums, target)
+
+  # 未找到 target ，返回 -1
+  return -1 if i == nums.length || nums[i] != target
+
+  i # 找到 target ，返回索引 i
+end
+
+### 二分查找最右一个 target ###
+def binary_search_right_edge(nums, target)
+  # 转化为查找最左一个 target + 1
+  i = binary_search_insertion(nums, target + 1)
+
+  # j 指向最右一个 target ，i 指向首个大于 target 的元素
+  j = i - 1
+
+  # 未找到 target ，返回 -1
+  return -1 if j == -1 || nums[j] != target
+
+  j # 找到 target ，返回索引 j
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  # 包含重复元素的数组
+  nums = [1, 3, 6, 6, 6, 6, 6, 10, 12, 15]
+  puts "\n数组 nums = #{nums}"
+
+  # 二分查找左边界和右边界
+  for target in [6, 7]
+    index = binary_search_left_edge(nums, target)
+    puts "最左一个元素 #{target} 的索引为 #{index}"
+    index = binary_search_right_edge(nums, target)
+    puts "最右一个元素 #{target} 的索引为 #{index}"
+  end
+end