C# 在较长序列中查找子序列
我需要在其他大序列中找到一个序列，例如，C# 在较长序列中查找子序列,c#,C#,我需要在其他大序列中找到一个序列，例如，{1,3,2,3}出现在{1,3,2,3,4,3}和{5,1,3,2,3}中。有没有办法用IEnumerable或其他方法快速完成这项工作？您可以尝试类似的方法开始。将此列表转换为字符串后，可以使用子字符串查找序列： if (String.Join(",", numericList.ConvertAll<string>(x => x.ToString()).ToArray()) { //get sequence } if（Str
{1,3,2,3}{1,3,2,3,4,3}{5,1,3,2,3}IEnumerableif (String.Join(",", numericList.ConvertAll<string>(x => x.ToString()).ToArray())
{
//get sequence
}
if（String.Join（“，”，numericslist.ConvertAll（x=>x.ToString（））.ToArray（））
{
//获取序列
}
Equals（）null{1,2,1,2,3}之类的东西时，这显然是不正确的）。ContainsSubsequence（{1,2,3})IEnumeratorpublic static bool ContainsSubequence<T>(this IEnumerable<T> parent, IEnumerable<T> target)
{
bool foundOneMatch = false;
var enumeratedTarget = target.ToList();
int enumPos = 0;
using (IEnumerator<T> parentEnum = parent.GetEnumerator())
{
while (parentEnum.MoveNext())
{
if (enumeratedTarget[enumPos].Equals(parentEnum.Current))
{
// Match, so move the target enum forward
foundOneMatch = true;
if (enumPos == enumeratedTarget.Count - 1)
{
// We went through the entire target, so we have a match
return true;
}
enumPos++;
}
else if (foundOneMatch)
{
foundOneMatch = false;
enumPos = 0;
if (enumeratedTarget[enumPos].Equals(parentEnum.Current))
{
foundOneMatch = true;
enumPos++;
}
}
}
return false;
}
}
公共静态bool包含序列（此IEnumerable父级，IEnumerable目标）
{
bool foundOneMatch=false；
var enumeratedTarget=target.ToList（）；
int-enumPos=0；
使用（IEnumerator parentEnum=parent.GetEnumerator（））
{
while（parentEnum.MoveNext（））
{
if（enumeratedTarget[enumPos].Equals（parentEnum.Current））
{
//匹配，因此向前移动目标枚举
foundOneMatch=true；
如果（enumPos==enumeratedTarget.Count-1）
{
//我们穿过了整个目标，所以我们有一场比赛
返回true；
}
enumPos++；
}
else if（foundOneMatch）
{
foundOneMatch=false；
enumPos=0；
if（enumeratedTarget[enumPos].Equals（parentEnum.Current））
{
foundOneMatch=true；
enumPos++；
}
}
}
返回false；
}
}
这段代码没有任何错误，但对于大（或无限）序列来说效果不佳。类似于@dlev，但它也处理
{1,1,2}。ContainsSubsequence（{1,1,2}）公共静态bool包含ssubsequence（此IEnumerable父级，IEnumerable目标）
{
var pattern=target.ToArray（）；
var source=new LinkedList（）；
foreach（父级中的var元素）
{
source.AddLast（元素）；
if（source.Count==pattern.Length）
{
if（source.SequenceEqual（模式））
返回true；
source.RemoveFirst（）；
}
}
返回false；
}
var a1 = new List<int> { 1, 2, 3, 4, 5 };
var a2 = new List<int> { 2, 3, 4 };
int index = -1;
bool res = a2.All(
x => index != -1 ? (++index == a1.IndexOf(x)) : ((index = a1.IndexOf(x)) != -1)
);
var a1=新列表{1,2,3,4,5}；
var a2=新列表{2,3,4}；
int指数=-1；
bool res=a2.全部(
x=>index！=-1？（++index==a1.IndexOf（x））：（（index=a1.IndexOf（x））！=-1）
);
public static bool ContainsSequence<T>(this List<T> parent, List<T> target)
{
for (int fromElement = parent.IndexOf(target.First());
(fromElement != -1) && (fromElement <= parent.Count - target.Count);
fromElement = parent.FindIndex(fromElement + 1, p => p.Equals(target.First())))
{
var comparedSequence = parent.Skip(fromElement).Take(target.Count);
if (comparedSequence.SequenceEqual(target)) return true;
}
return false;
}
公共静态bool包含序列（此列表父级，列表目标）
{
for（int-fromElement=parent.IndexOf（target.First（））；
（fromElement！=-1）&（fromElement p.Equals（target.First（）））
{
var comparedSequence=parent.Skip（fromElement）.Take（target.Count）；
if（comparedSequence.SequenceEqual（target））返回true；
}
返回false；
}
public static bool ContainsList<T>(this List<T> containingList, List<T> containedList)
{
string strContaining = "," + string.Join(",", containingList) + ",";
string strContained = "," + string.Join(",", containedList) + ",";
return strContaining.Contains(strContained);
}
这是一个研究得很好的问题，根据我的研究，有两种算法是可行的 即算法和算法 我谨此陈辞 它被写来处理长度不确定的源或父序列，最大可达 正如我们所看到的，内部实现返回子字符串或目标模式出现的索引序列 你可以这样简单地使用它
var contains = new[] { 1, 3, 2, 3, 4, 3 }.Contains(new[] { 1, 3, 2, 3 });
namespace Code
{
using System;
using System.Collections.Generic;
using System.Linq;
/// <summary>
/// A generic implementation of the Knuth-Morris-Pratt algorithm that searches,
/// in a memory efficient way, over a given <see cref="IEnumerable{T}"/>.
/// </summary>
public static class KMP
{
/// <summary>
/// Determines whether a sequence contains the search string.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>
/// </typeparam>
/// <param name="source">
/// A sequence of elements
/// </param>
/// <param name="pattern">The search string.</param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// If <c>null</c>
/// <see cref="EqualityComparer{T}.Default"/> will be used.
/// </param>
/// <returns>
/// <c>true</c> if the source contains the specified pattern;
/// otherwise, <c>false</c>.
/// </returns>
/// <exception cref="ArgumentNullException">pattern</exception>
public static bool Contains<T>(
this IEnumerable<T> source,
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer = null)
{
if (pattern == null)
{
throw new ArgumentNullException(nameof(pattern));
}
equalityComparer = equalityComparer ?? EqualityComparer<T>.Default;
return SearchImplementation(source, pattern, equalityComparer).Any();
}
public static IEnumerable<long> IndicesOf<T>(
this IEnumerable<T> source,
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer = null)
{
if (pattern == null)
{
throw new ArgumentNullException(nameof(pattern));
}
equalityComparer = equalityComparer ?? EqualityComparer<T>.Default;
return SearchImplementation(source, pattern, equalityComparer);
}
/// <summary>
/// Identifies indices of a pattern string in a given sequence.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>
/// </typeparam>
/// <param name="source">
/// The sequence to search.
/// </param>
/// <param name="patternString">
/// The string to find in the sequence.
/// </param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// </param>
/// <returns>
/// A sequence of indices where the pattern can be found
/// in the source.
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// patternSequence - The pattern must contain 1 or more elements.
/// </exception>
private static IEnumerable<long> SearchImplementation<T>(
IEnumerable<T> source,
IEnumerable<T> patternString,
IEqualityComparer<T> equalityComparer)
{
// Pre-process the pattern
(var slide, var pattern) = GetSlide(patternString, equalityComparer);
var patternLength = pattern.Count;
if (patternLength == 0)
{
throw new ArgumentOutOfRangeException(
nameof(patternString),
"The pattern must contain 1 or more elements.");
}
var buffer = new Dictionary<long, T>(patternLength);
var more = true;
long sourceIndex = 0; // index for source
int patternIndex = 0; // index for pattern
using(var sourceEnumerator = source.GetEnumerator())
while (more)
{
more = FillBuffer(
buffer,
sourceEnumerator,
sourceIndex,
patternLength,
out T t);
if (equalityComparer.Equals(pattern[patternIndex], t))
{
patternIndex++;
sourceIndex++;
more = FillBuffer(
buffer,
sourceEnumerator,
sourceIndex,
patternLength,
out t);
}
if (patternIndex == patternLength)
{
yield return sourceIndex - patternIndex;
patternIndex = slide[patternIndex - 1];
}
else if (more && !equalityComparer.Equals(pattern[patternIndex], t))
{
if (patternIndex != 0)
{
patternIndex = slide[patternIndex - 1];
}
else
{
sourceIndex = sourceIndex + 1;
}
}
}
}
/// <summary>
/// Services the buffer and retrieves the value.
/// </summary>
/// <remarks>
/// The buffer is used so that it is not necessary to hold the
/// entire source in memory.
/// </remarks>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>.
/// </typeparam>
/// <param name="buffer">The buffer.</param>
/// <param name="source">The source enumerator.</param>
/// <param name="sourceIndex">The element index to retrieve.</param>
/// <param name="patternLength">Length of the search string.</param>
/// <param name="value">The element value retrieved from the source.</param>
/// <returns>
/// <c>true</c> if there is potentially more data to process;
/// otherwise <c>false</c>.
/// </returns>
private static bool FillBuffer<T>(
IDictionary<long, T> buffer,
IEnumerator<T> source,
long sourceIndex,
int patternLength,
out T value)
{
bool more = true;
if (!buffer.TryGetValue(sourceIndex, out value))
{
more = source.MoveNext();
if (more)
{
value = source.Current;
buffer.Remove(sourceIndex - patternLength);
buffer.Add(sourceIndex, value);
}
}
return more;
}
/// <summary>
/// Gets the offset array which acts as a slide rule for the KMP algorithm.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>.
/// </typeparam>
/// <param name="pattern">The search string.</param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// If <c>null</c>
/// <see cref="EqualityComparer{T}.Default"/> will be used.
/// </param>
/// <returns>A tuple of the offsets and the enumerated pattern.</returns>
private static (IReadOnlyList<int> Slide, IReadOnlyList<T> Pattern) GetSlide<T>(
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer)
{
var patternList = pattern.ToList();
var slide = new int[patternList.Count];
int length = 0;
int patternIndex = 1;
while (patternIndex < patternList.Count)
{
if (equalityComparer.Equals(
patternList[patternIndex],
patternList[length]))
{
length++;
slide[patternIndex] = length;
patternIndex++;
}
else
{
if (length != 0)
{
length = slide[length - 1];
}
else
{
slide[patternIndex] = length;
patternIndex++;
}
}
}
return (slide, patternList);
}
}
}
名称空间代码
{
使用制度；
使用System.Collections.Generic；
使用System.Linq；
///
///Knuth-Morris-Pratt算法的通用实现，用于搜索，
///以内存有效的方式，在给定的时间内。
///
公共静态类KMP
{
///
///确定序列是否包含搜索字符串。
///
///
///元素的类型
///
///
///元素序列
///
///搜索字符串。
///
///确定序列是否包含指定的元素。
///如果为空
///将使用。
///
///
///如果源包含指定的模式，则为true；
///否则，错误。
///
///图案
公共静态布尔包含(
这是一个数不清的来源，
可数模式，
IEqualityComparer equalityComparer=null）
{
if（pattern==null）
{
抛出新的ArgumentNullException（nameof（pattern））；
}
equalityComparer=equalityComparer？？equalityComparer.Default；
返回SearchImplementation（source、pattern、equalityComparer）.Any（）；
}
公共静态IEnumerable指标(
public static bool ContainsList<T>(this List<T> containingList, List<T> containedList)
{
string strContaining = "," + string.Join(",", containingList) + ",";
string strContained = "," + string.Join(",", containedList) + ",";
return strContaining.Contains(strContained);
}
if (bigList.ContainsList(smallList))
{
...
}
var contains = new[] { 1, 3, 2, 3, 4, 3 }.Contains(new[] { 1, 3, 2, 3 });
namespace Code
{
using System;
using System.Collections.Generic;
using System.Linq;
/// <summary>
/// A generic implementation of the Knuth-Morris-Pratt algorithm that searches,
/// in a memory efficient way, over a given <see cref="IEnumerable{T}"/>.
/// </summary>
public static class KMP
{
/// <summary>
/// Determines whether a sequence contains the search string.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>
/// </typeparam>
/// <param name="source">
/// A sequence of elements
/// </param>
/// <param name="pattern">The search string.</param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// If <c>null</c>
/// <see cref="EqualityComparer{T}.Default"/> will be used.
/// </param>
/// <returns>
/// <c>true</c> if the source contains the specified pattern;
/// otherwise, <c>false</c>.
/// </returns>
/// <exception cref="ArgumentNullException">pattern</exception>
public static bool Contains<T>(
this IEnumerable<T> source,
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer = null)
{
if (pattern == null)
{
throw new ArgumentNullException(nameof(pattern));
}
equalityComparer = equalityComparer ?? EqualityComparer<T>.Default;
return SearchImplementation(source, pattern, equalityComparer).Any();
}
public static IEnumerable<long> IndicesOf<T>(
this IEnumerable<T> source,
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer = null)
{
if (pattern == null)
{
throw new ArgumentNullException(nameof(pattern));
}
equalityComparer = equalityComparer ?? EqualityComparer<T>.Default;
return SearchImplementation(source, pattern, equalityComparer);
}
/// <summary>
/// Identifies indices of a pattern string in a given sequence.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>
/// </typeparam>
/// <param name="source">
/// The sequence to search.
/// </param>
/// <param name="patternString">
/// The string to find in the sequence.
/// </param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// </param>
/// <returns>
/// A sequence of indices where the pattern can be found
/// in the source.
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// patternSequence - The pattern must contain 1 or more elements.
/// </exception>
private static IEnumerable<long> SearchImplementation<T>(
IEnumerable<T> source,
IEnumerable<T> patternString,
IEqualityComparer<T> equalityComparer)
{
// Pre-process the pattern
(var slide, var pattern) = GetSlide(patternString, equalityComparer);
var patternLength = pattern.Count;
if (patternLength == 0)
{
throw new ArgumentOutOfRangeException(
nameof(patternString),
"The pattern must contain 1 or more elements.");
}
var buffer = new Dictionary<long, T>(patternLength);
var more = true;
long sourceIndex = 0; // index for source
int patternIndex = 0; // index for pattern
using(var sourceEnumerator = source.GetEnumerator())
while (more)
{
more = FillBuffer(
buffer,
sourceEnumerator,
sourceIndex,
patternLength,
out T t);
if (equalityComparer.Equals(pattern[patternIndex], t))
{
patternIndex++;
sourceIndex++;
more = FillBuffer(
buffer,
sourceEnumerator,
sourceIndex,
patternLength,
out t);
}
if (patternIndex == patternLength)
{
yield return sourceIndex - patternIndex;
patternIndex = slide[patternIndex - 1];
}
else if (more && !equalityComparer.Equals(pattern[patternIndex], t))
{
if (patternIndex != 0)
{
patternIndex = slide[patternIndex - 1];
}
else
{
sourceIndex = sourceIndex + 1;
}
}
}
}
/// <summary>
/// Services the buffer and retrieves the value.
/// </summary>
/// <remarks>
/// The buffer is used so that it is not necessary to hold the
/// entire source in memory.
/// </remarks>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>.
/// </typeparam>
/// <param name="buffer">The buffer.</param>
/// <param name="source">The source enumerator.</param>
/// <param name="sourceIndex">The element index to retrieve.</param>
/// <param name="patternLength">Length of the search string.</param>
/// <param name="value">The element value retrieved from the source.</param>
/// <returns>
/// <c>true</c> if there is potentially more data to process;
/// otherwise <c>false</c>.
/// </returns>
private static bool FillBuffer<T>(
IDictionary<long, T> buffer,
IEnumerator<T> source,
long sourceIndex,
int patternLength,
out T value)
{
bool more = true;
if (!buffer.TryGetValue(sourceIndex, out value))
{
more = source.MoveNext();
if (more)
{
value = source.Current;
buffer.Remove(sourceIndex - patternLength);
buffer.Add(sourceIndex, value);
}
}
return more;
}
/// <summary>
/// Gets the offset array which acts as a slide rule for the KMP algorithm.
/// </summary>
/// <typeparam name="T">
/// The type of elements of <paramref name="source"/>.
/// </typeparam>
/// <param name="pattern">The search string.</param>
/// <param name="equalityComparer">
/// Determines whether the sequence contains a specified element.
/// If <c>null</c>
/// <see cref="EqualityComparer{T}.Default"/> will be used.
/// </param>
/// <returns>A tuple of the offsets and the enumerated pattern.</returns>
private static (IReadOnlyList<int> Slide, IReadOnlyList<T> Pattern) GetSlide<T>(
IEnumerable<T> pattern,
IEqualityComparer<T> equalityComparer)
{
var patternList = pattern.ToList();
var slide = new int[patternList.Count];
int length = 0;
int patternIndex = 1;
while (patternIndex < patternList.Count)
{
if (equalityComparer.Equals(
patternList[patternIndex],
patternList[length]))
{
length++;
slide[patternIndex] = length;
patternIndex++;
}
else
{
if (length != 0)
{
length = slide[length - 1];
}
else
{
slide[patternIndex] = length;
patternIndex++;
}
}
}
return (slide, patternList);
}
}
}