feat: add ruby codes - chapter greedy (#1350)

codes/ruby/chapter_greedy/max_capacity.rb

@@ -0,0 +1,37 @@
+=begin
+File: max_capacity.rb
+Created Time: 2024-05-07
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+### 最大容量：贪心 ###
+def max_capacity(ht)
+  # 初始化 i, j，使其分列数组两端
+  i, j = 0, ht.length - 1
+  # 初始最大容量为 0
+  res = 0
+
+  # 循环贪心选择，直至两板相遇
+  while i < j
+    # 更新最大容量
+    cap = [ht[i], ht[j]].min * (j - i)
+    res = [res, cap].max
+    # 向内移动短板
+    if ht[i] < ht[j]
+      i += 1
+    else
+      j -= 1
+    end
+  end
+
+  res
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  ht = [3, 8, 5, 2, 7, 7, 3, 4]
+
+  # 贪心算法
+  res = max_capacity(ht)
+  puts "最大容量为 #{res}"
+end