Find longest common prefix?

Question

In two strings:

\"Mary Had a Little Lamb\"
\"Mary Had a Big Lamb\"

should return

\"Mary Had a \"

Answer 1

This solution applied to a multiple string array. When you have 3 or 4 strings, it's better to use StringBuilder. For 2 strings, it's ok to use substring. Code in C#:

    public string LongestCommonPrefix(string[] strs) {
    if(strs.Length == 0) return string.Empty;

    Array.Sort(strs);

    var first = strs[0];
    var last = strs[strs.Length - 1];

    var sb = new StringBuilder();
    for(int i = 0; i< first.Length; i++)
    {
        if(first[i] != last[i])
        {
            break;
        }
        sb.Append(first[i]);
    }

    return sb.ToString();
}