[英]Longest subsequence in array
我正在嘗試使用 List 解決我的任務,我知道我非常接近解決它,但我現在被卡住了。 代碼中有問題,我無法弄清楚它是什么。 你能不能看看並幫助:
/*
Write a program that reads an array of integers and removes from it a minimal number of elements in such way that the
remaining array is sorted in increasing order. Print the remaining sorted array.
Example: {6, 1, 4, 3, 0, 3, 6, 4, 5} {1, 3, 3, 4, 5}
*/
using System;
using System.Collections.Generic;
class RemoveMinimalElements
{
static void Main()
{
int n;
n = int.Parse(Console.ReadLine());
List<int> arr = new List<int>();
List<int> sorted = new List<int>();
int maxSubsetLenght = 0;
for (int i = 0; i < n; i++)
{
arr.Add(int.Parse(Console.ReadLine()));
}
for (int i = 1; i <= (int)Math.Pow(2, n) - 1; i++)
{
int tempSubsetLenght = 0;
string tempString = "";
List<int> temp = new List<int>();
for (int j = 1; j <= n; j++)
{
int andMask = i & (1 << j);
int bit = andMask >> j;
if (bit == 1)
{
temp.Add(arr[n - 1 - j]);
tempSubsetLenght++;
}
if (tempSubsetLenght > maxSubsetLenght)
{
maxSubsetLenght = tempSubsetLenght;
for(int k =1; k < temp.Count; k ++)
{
if (temp[k] >= temp[k - 1])
{
sorted = temp;
}
}
}
}
}
for (int i = sorted.Count - 1; i > 0; i--)
{
Console.WriteLine(sorted[i]);
}
}
}
我沒有遵循代碼,我只是測試了您的應用程序。
這是我的第一個輸入:5。
然后我輸入了這 5 個輸入 2,4,6,8,10 所以
arr = {2,4,6,8,10};
當涉及到最后幾行時,它給了我ArguementOutOfRangeException (Index was out of range. Must be non-negative and less than the size of the collection.)
因為它試圖獲取 arr[item] 並且 item 是 6 所以它試圖獲取不存在的arr[6]
。
我不知道詳盡搜索是否適合您的情況,但這對您有用嗎?
static void Main(string[] args)
{
int[] input = new[] { 6, 1, 4, 3, 0, 3, 6, 4, 5 };
int[] expectedOutput = new[] { 1, 3, 3, 4, 5 };
int[] solution = TryGetSolution(input);
Console.WriteLine("Input: " + FormatNumbers(input));
Console.WriteLine("Expected Output: " + FormatNumbers(expectedOutput));
Console.WriteLine("Output: " + FormatNumbers(solution));
Console.ReadLine();
}
private static string FormatNumbers(int[] numbers)
{
return string.Join(", ", numbers);
}
private static int[] TryGetSolution(int[] input)
{
return TryWithoutAnyItem(input);
}
private static int[] TryWithoutAnyItem(int[] items)
{
return Enumerable.Range(0, items.Length)
.Select(i => TryWithoutItem(items, i))
.Where(solution => solution != null)
.OrderByDescending(solution => solution.Length)
.FirstOrDefault();
}
private static int[] TryWithoutItem(int[] items, int withoutIndex)
{
if (IsSorted(items)) return items;
var removed = items.Take(withoutIndex).Concat(items.Skip(withoutIndex + 1));
return TryWithoutAnyItem(removed.ToArray());
}
private static bool IsSorted(IEnumerable<int> items)
{
return items.Zip(items.Skip(1), (a, b) => a.CompareTo(b)).All(c => c <= 0);
}
}
我解決了! 非常感謝您的支持。 我是初學者,我還不能使用和理解更困難的東西,所以這是我用我已經知道的東西所做的:
/*
Write a program that reads an array of integers and removes from it a minimal number of elements in such way that the
remaining array is sorted in increasing order. Print the remaining sorted array.
Example: {6, 1, 4, 3, 0, 3, 6, 4, 5} {1, 3, 3, 4, 5}
*/
using System;
using System.Collections.Generic;
class RemoveMinimalElements
{
static bool CheckAscending(List<int> list)
{
bool ascending = true;
for (int i = 0; i < list.Count - 1; i++)
{
if (list[i] > list[i + 1])
{
ascending = false;
}
}
return ascending;
}
static void Main()
{
int n;
n = int.Parse(Console.ReadLine());
List<int> arr = new List<int>();
List<int> sorted = new List<int>();
int maxSubsetLenght = 0;
for (int i = 0; i < n; i++)
{
arr.Add(int.Parse(Console.ReadLine()));
}
for (int i = 1; i <= (int)Math.Pow(2, n) - 1; i++)
{
int tempSubsetLenght = 0;
List<int> temp = new List<int>();
for (int j = 1; j <= n; j++)
{
if (((i >> (j - 1)) & 1) == 1)
{
temp.Add(arr[j - 1]);
tempSubsetLenght++;
}
}
if ((tempSubsetLenght > maxSubsetLenght) && (CheckAscending(temp)))
{
sorted = temp;
maxSubsetLenght = tempSubsetLenght;
}
}
for (int i = 0; i < sorted.Count; i++)
{
Console.WriteLine(sorted[i]);
}
}
}
這對我有用
private static void FindLongestRisingSequence(int[] inputArray)
{
int[] array = inputArray;
List<int> list = new List<int>();
List<int> longestList = new List<int>();
int highestCount = 1;
for (int i = 0; i < array.Length; i++)
{
list.Add(array[i]);
for (int j = i+1; j < array.Length; j++)
{
if (array[i] < array[j])
{
list.Add(array[j]);
i++;
}
else
{
break;
}
i = j;
}
// Compare with in previous lists
if (highestCount < list.Count)
{
highestCount = list.Count;
longestList = new List<int>(list);
}
list.Clear();
}
Console.WriteLine();
// Print list
Console.WriteLine("The longest subsequence");
foreach (int iterator in longestList)
{
Console.Write(iterator + " ");
}
Console.WriteLine();
}
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