算法导论-钢条切割 C# 递归实现

下班前看到有位兄弟写 钢条切割问题，尝试实现C#版， 还没有实现最优版，分享一下。

int[] parr;



 private void button1_Click(object sender, EventArgs e)

        {

            //策略标准，如 总长度 7 取第1位，6位 , 最优结果是:  18 = 1 + 17 

            parr = new int[] { 

                1 , 5 , 8 , 9 , 10 , 17 , 17 , 20 , 45 , 30

            };



            Stack<int> stack = new Stack<int>();



            //总容量

            int maxLength = 7 ;



            int result = compute(parr, maxLength, ref stack);

            int c = stack.Count;



            Console.WriteLine("切割:");



            int temp;

            while (c-- > 0) {

                Console.WriteLine(temp = stack.Pop());

            }



          



            Console.WriteLine("结果:{0}", result);

        }

 

核心部分:

  /// <summary>

        /// 

        /// </summary>

        /// <param name="p">策略标准</param>

        /// <param name="length">分割集合</param>

        /// <param name="stack">分割步骤</param>

        /// <returns></returns>

        int compute(int[] p, int length, ref  Stack<int> stack)

        {

            int price = 0;



            //最优方案

            int maxPrice = 0;



            //截止目前 本轮最优方案步骤

            Stack<int> __stack = null;



            //临时方案步骤

            Stack<int> _stackTemp = null  ;



            int split;



            if (length == 0)

                return 0;



            for (int i = 1; i <= length ; i++ )

            {

                if (i >= p.Length)

                {

                    split = p.Length;

                    

                }

                else

                {

                    split = i;

                }



                //临时方案

                _stackTemp = new Stack<int>();



                price = p[split - 1] + compute(p, length - split, ref _stackTemp);

                

                if (maxPrice < price)

                {

                    //新方案

                    maxPrice = price;

                    _stackTemp.Push(split);



                    //更新本轮最优方案

                    __stack = _stackTemp;

                }

            }



            //将本轮最优方案添加到全局方案集

            while (__stack.Count > 0) {

                stack.Push(__stack.Pop());

            }

            

            //返回最优结果

            return maxPrice;

        }

 

结果: