动态编程最长递增子序列

Question

我需要帮助来了解这一点 。 如何指定父级列表中的元素-就像它所引用的序列中上一个元素的哪个列表一样？ 我已经尝试过对每个列表进行测试，但仍得到另一个父列表。 抱歉，这是一个愚蠢的问题。

Answer 1

查看此Java代码以了解解决方案

 /* A Naive Java Program for LIS Implementation */ class LIS { static int max_ref; // stores the LIS /* To make use of recursive calls, this function must return two things: 1) Length of LIS ending with element arr[n-1]. We use max_ending_here for this purpose 2) Overall maximum as the LIS may end with an element before arr[n-1] max_ref is used this purpose. The value of LIS of full array of size n is stored in *max_ref which is our final result */ static int _lis(int arr[], int n) { // base case if (n == 1) return 1; // 'max_ending_here' is length of LIS ending with arr[n-1] int res, max_ending_here = 1; /* Recursively get all LIS ending with arr[0], arr[1] ... arr[n-2]. If arr[i-1] is smaller than arr[n-1], and max ending with arr[n-1] needs to be updated, then update it */ for (int i = 1; i < n; i++) { res = _lis(arr, i); if (arr[i-1] < arr[n-1] && res + 1 > max_ending_here) max_ending_here = res + 1; } // Compare max_ending_here with the overall max. And // update the overall max if needed if (max_ref < max_ending_here) max_ref = max_ending_here; // Return length of LIS ending with arr[n-1] return max_ending_here; } // The wrapper function for _lis() static int lis(int arr[], int n) { // The max variable holds the result max_ref = 1; // The function _lis() stores its result in max _lis( arr, n); // returns max return max_ref; } // driver program to test above functions public static void main(String args[]) { int arr[] = { 10, 22, 9, 33, 21, 50, 41, 60 }; int n = arr.length; System.out.println("Length of lis is " + lis(arr, n) + "n"); } }