LeetCode-in-Java

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 (!temp.isEmpty() && 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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