[LeetCode] Problem 14 - Longest Common Prefix

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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

No.1

Input: [“flower”,”flow”,”flight”]

Output: “fl”

No.2

Input: [“dog”,”racecar”,”car”]

Output: “”

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

Note

All given inputs are in lowercase letters a-z.

Code

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public String longestCommonPrefix(String[] strs) {
    if (strs == null || strs.length < 1)
        return "";

    for (int i = 0; i < strs[0].length(); i++) {
        for (int j = 1; j < strs.length; j++) {
            if (i == strs[j].length() || strs[j].charAt(i) != strs[0].charAt(i))
                return strs[0].substring(0, i);
        }
    }

    return strs[0];
}