14. Longest Common Prefix

class Solution {
    public String longestCommonPrefix(String[] strs) {
        if (strs.length == 0) return "";
        String prefix = strs[0];
        for (int i = 1; i < strs.length; i++)
            while (strs[i].indexOf(prefix) != 0) {
                prefix = prefix.substring(0, prefix.length() - 1);
            if (prefix.isEmpty()) return "";
            }        
        return prefix;
    }
}

Runtime: 0 ms, faster than 100.00% of Java online submissions for Longest Common Prefix.
Memory Usage: 36.9 MB, less than 90.83% of Java online submissions for Longest Common Prefix.