在字符串数组中查找最长的子字符串,并将其从数组中的所有元素中删除

Question

我有这个数组,例如(大小是可变的):

x = ["10111", "10122", "10250", "10113"]

我需要找到最长的字符串,它是每个数组元素的子字符串(在本例中为"10")(它不必是字符串的前缀).我必须从所有字符串中删除它.此示例的输出将是:

x=["111","222","250","113"] //common value = "10"

Answer 1

此扩展名找到最长的最常见子字符串.请注意,"1"每个字符串中包含的内容甚至更多"10".(仅限C#):

public static class StringExtensions
{
    public static IEnumerable<string> GetMostCommonSubstrings(this IList<string> strings)
    {
        if (strings == null)
            throw new ArgumentNullException("strings");
        if (!strings.Any() || strings.Any(s => string.IsNullOrEmpty(s)))
            throw new ArgumentException("None string must be empty", "strings");

        var allSubstrings = new List<List<string>>();
        for (int i = 0; i < strings.Count; i++)
        {
            var substrings = new List<string>();
            string str = strings[i];
            for (int c = 0; c < str.Length - 1; c++)
            {
                for (int cc = 1; c + cc <= str.Length; cc++)
                {
                    string substr = str.Substring(c, cc);
                    if (allSubstrings.Count < 1 || allSubstrings.Last().Contains(substr))
                        substrings.Add(substr);
                }
            }
            allSubstrings.Add(substrings);
        }
        if (allSubstrings.Last().Any())
        {
            var mostCommon = allSubstrings.Last()
                .GroupBy(str => str)
                .OrderByDescending(g => g.Key.Length)
                .ThenByDescending(g => g.Count())
                .Select(g => g.Key);
            return mostCommon;
        }
        return Enumerable.Empty<string>();
    }
}

现在很简单:

string[] x = new[] { "10111", "10122", "10250", "10113" };
string mostCommonSubstring = x.GetMostCommonSubstrings().FirstOrDefault();
if (mostCommonSubstring != null)
{
    for (int i = 0; i < x.Length; i++)
        x[i] = x[i].Replace(mostCommonSubstring, "");
}
Console.Write(string.Join(", ", x));

输出:

111, 122, 250, 113

DEMO

编辑:如果您只是想在不考虑出现频率的情况下找到最长的公共子字符串,可以使用以下方法使用此优化方法(O(n)操作)HashSet<string>:

public static string GetLongestCommonSubstring(this IList<string> strings)
{
    if (strings == null)
        throw new ArgumentNullException("strings");
    if (!strings.Any() || strings.Any(s => string.IsNullOrEmpty(s)))
        throw new ArgumentException("None string must be empty", "strings");

    var commonSubstrings = new HashSet<string>(strings[0].GetSubstrings());
    foreach (string str in strings.Skip(1))
    {
        commonSubstrings.IntersectWith(str.GetSubstrings());
        if (commonSubstrings.Count == 0)
            return null;
    }
    return commonSubstrings.OrderByDescending(s => s.Length).First();
}

public static IEnumerable<string> GetSubstrings(this string str)
{
    if (string.IsNullOrEmpty(str))
        throw new ArgumentException("str must not be null or empty", "str");

    for (int c = 0; c < str.Length - 1; c++)
    {
        for (int cc = 1; c + cc <= str.Length; cc++)
        {
            yield return str.Substring(c, cc);
        }
    }
}

以这种方式使用它:

string[] x = new[] { "101133110", "101233210", "102533010", "101331310" };
string longestCommon = x.GetLongestCommonSubstring();  // "10"