Bug fixes and improvements (#1380)

* preorder, inorder, postorder -> pre-order, in-order, post-order

* Bug fixes

* Bug fixes

* Update what_is_dsa.md

* Sync zh and zh-hant versions

* Sync zh and zh-hant versions.

* Update performance_evaluation.md and time_complexity.md

* Add @khoaxuantu to the landing page.

* Sync zh and zh-hant versions

* Add @ khoaxuantu to the landing page of zh-hant and en versions.

zh-hant/codes/ruby/chapter_dynamic_programming/unbounded_knapsack.rb

@@ -0,0 +1,61 @@
+=begin
+File: unbounded_knapsack.rb
+Created Time: 2024-05-29
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+### 完全背包：動態規劃 ###
+def unbounded_knapsack_dp(wgt, val, cap)
+  n = wgt.length
+  # 初始化 dp 表
+  dp = Array.new(n + 1) { Array.new(cap + 1, 0) }
+  # 狀態轉移
+  for i in 1...(n + 1)
+    for c in 1...(cap + 1)
+      if wgt[i - 1] > c
+        # 若超過背包容量，則不選物品 i
+        dp[i][c] = dp[i - 1][c]
+      else
+        # 不選和選物品 i 這兩種方案的較大值
+        dp[i][c] = [dp[i - 1][c], dp[i][c - wgt[i - 1]] + val[i - 1]].max
+      end
+    end
+  end
+  dp[n][cap]
+end
+
+### 完全背包：空間最佳化後的動態規劃 ##3
+def unbounded_knapsack_dp_comp(wgt, val, cap)
+  n = wgt.length
+  # 初始化 dp 表
+  dp = Array.new(cap + 1, 0)
+  # 狀態轉移
+  for i in 1...(n + 1)
+    # 正序走訪
+    for c in 1...(cap + 1)
+      if wgt[i -1] > c
+        # 若超過背包容量，則不選物品 i
+        dp[c] = dp[c]
+      else
+        # 不選和選物品 i 這兩種方案的較大值
+        dp[c] = [dp[c], dp[c - wgt[i - 1]] + val[i - 1]].max
+      end
+    end
+  end
+  dp[cap]
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  wgt = [1, 2, 3]
+  val = [5, 11, 15]
+  cap = 4
+
+  # 動態規劃
+  res = unbounded_knapsack_dp(wgt, val, cap)
+  puts "不超過背包容量的最大物品價值為 #{res}"
+
+  # 空間最佳化後的動態規劃
+  res = unbounded_knapsack_dp_comp(wgt, val, cap)
+  puts "不超過背包容量的最大物品價值為 #{res}"
+end