LeetCode in Net

14. Longest Common Prefix

Easy

Write a function to find the longest common prefix string amongst an array of strings.

If there is no common prefix, return an empty string "".

Example 1:

Input: strs = [“flower”,”flow”,”flight”]

Output: “fl”

Example 2:

Input: strs = [“dog”,”racecar”,”car”]

Output: “”

Explanation: There is no common prefix among the input strings.

Constraints:

• 1 <= strs.length <= 200
• 0 <= strs[i].length <= 200
• strs[i] consists of only lower-case English letters.

Solution

public class Solution
{
    public string LongestCommonPrefix(string[] strs)
    {
        if (strs.Length < 1)
        {
            return "";
        }
        if (strs.Length == 1)
        {
            return strs[0];
        }
        string temp = strs[0];
        int i = 1;
        string cur;
        while (!string.IsNullOrEmpty(temp) && i < strs.Length)
        {
            if (temp.Length > strs[i].Length)
            {
                temp = temp.Substring(0, strs[i].Length);
            }
            cur = strs[i].Substring(0, temp.Length);
            if (!cur.Equals(temp))
            {
                temp = temp.Substring(0, temp.Length - 1);
            }
            else
            {
                i++;
            }
        }
        return temp;
    }
}

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