[Leetcode] Longest Common Prefix

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

Compare words by words to find the longest common prefix.

    public String longestCommonPrefix(String[] strs) {
        int n = strs.length;
        if(n == 0)
            return ""; // corner case
        String com = strs[0];
        for(int i = 1; i < n; i++) {
            int len = Math.min(com.length(), strs[i].length());
            int p = 0;
            while(p < len && com.charAt(p) == strs[i].charAt(p))
                p++;
            com = com.substring(0, p);
        }
        return com;
    }

Another way is to try to find the first character that differs.

    public String longestCommonPrefix(String[] strs) {
        int n = strs.length;
        if(n == 0)
            return ""; // corner case
        int len = strs[0].length();
        int i = 0;
        for(i = 0; i < len; i++) {
            for(int j = 0; j < n; j++) {
                if(strs[j].length() <= i || strs[j].charAt(i) != strs[0].charAt(i)) // the first position that differs
                    return strs[0].substring(0, i);
            }
        }
        return strs[0].substring(0, i);
    }