build

docs/chapter_dynamic_programming/dp_problem_features.md

@@ -304,7 +304,18 @@ $$
 === "Ruby"
 
     ```ruby title="min_cost_climbing_stairs_dp.rb"
-    [class]{}-[func]{min_cost_climbing_stairs_dp}
+    ### 爬楼梯最小代价：动态规划 ###
+    def min_cost_climbing_stairs_dp(cost)
+      n = cost.length - 1
+      return cost[n] if n == 1 || n == 2
+      # 初始化 dp 表，用于存储子问题的解
+      dp = Array.new(n + 1, 0)
+      # 初始状态：预设最小子问题的解
+      dp[1], dp[2] = cost[1], cost[2]
+      # 状态转移：从较小子问题逐步求解较大子问题
+      (3...(n + 1)).each { |i| dp[i] = [dp[i - 1], dp[i - 2]].min + cost[i] }
+      dp[n]
+    end
     ```
 
 === "Zig"
@@ -569,7 +580,27 @@ $$
 === "Ruby"
 
     ```ruby title="min_cost_climbing_stairs_dp.rb"
-    [class]{}-[func]{min_cost_climbing_stairs_dp_comp}
+    ### 爬楼梯最小代价：动态规划 ###
+    def min_cost_climbing_stairs_dp(cost)
+      n = cost.length - 1
+      return cost[n] if n == 1 || n == 2
+      # 初始化 dp 表，用于存储子问题的解
+      dp = Array.new(n + 1, 0)
+      # 初始状态：预设最小子问题的解
+      dp[1], dp[2] = cost[1], cost[2]
+      # 状态转移：从较小子问题逐步求解较大子问题
+      (3...(n + 1)).each { |i| dp[i] = [dp[i - 1], dp[i - 2]].min + cost[i] }
+      dp[n]
+    end
+
+    # 爬楼梯最小代价：空间优化后的动态规划
+    def min_cost_climbing_stairs_dp_comp(cost)
+      n = cost.length - 1
+      return cost[n] if n == 1 || n == 2
+      a, b = cost[1], cost[2]
+      (3...(n + 1)).each { |i| a, b = b, [a, b].min + cost[i] }
+      b
+    end
     ```
 
 === "Zig"
@@ -935,7 +966,23 @@ $$
 === "Ruby"
 
     ```ruby title="climbing_stairs_constraint_dp.rb"
-    [class]{}-[func]{climbing_stairs_constraint_dp}
+    ### 带约束爬楼梯：动态规划 ###
+    def climbing_stairs_constraint_dp(n)
+      return 1 if n == 1 || n == 2
+
+      # 初始化 dp 表，用于存储子问题的解
+      dp = Array.new(n + 1) { Array.new(3, 0) }
+      # 初始状态：预设最小子问题的解
+      dp[1][1], dp[1][2] = 1, 0
+      dp[2][1], dp[2][2] = 0, 1
+      # 状态转移：从较小子问题逐步求解较大子问题
+      for i in 3...(n + 1)
+        dp[i][1] = dp[i - 1][2]
+        dp[i][2] = dp[i - 2][1] + dp[i - 2][2]
+      end
+
+      dp[n][1] + dp[n][2]
+    end
     ```
 
 === "Zig"