LeetCode #14 Longest Common Prefix (E)

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        if (strs.length == 0) {
            return "";
        }
        
        if (strs.length == 1) {
            return strs[0];
        } 
        
        int idx = 0;
        boolean flag = true;
        while (idx < strs[0].length()) {
            char c = strs[0].charAt(idx);
            for (int i = 1; i < strs.length; i++) {
                if (idx >= strs[i].length() || strs[i].charAt(idx) != c) {
                    flag = false;
                    break;
                }
            }
            
            if (flag) {
                idx++;
            } else {
                break;
            }
        }
        
        return strs[0].substring(0, idx);
    }
}