14. Longest Common Prefix

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: ["flower","flow","flight"]
Output: "fl"

Example 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.

大佬解答： http://www.cnblogs.com/grandyang/p/4606926.html

class Solution {
    public String longestCommonPrefix(String[] strs) {
        String res = "";
        if(strs==null||strs.length==0) return "";
        for(int j = 0; j< strs[0].length(); j++){
            char c = strs[0].charAt(j);
            for(int i = 1; i<strs.length; i++){
                if(j>strs[i].length()||c!=strs[i].charAt(j)){
                    return res;
                }
            }
            res += Character.toString(c);
        }
        return res;
    }
}

　　

class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(strs.length == 0) return "";
        for(int i = 0; i < strs[0].length(); i++){//纵向扫描
            char c = strs[0].charAt(i);
            for(int j = 1; j < strs.length; j++){
                if(i == strs[j].length() || c != strs[j].charAt(i))
                    return strs[0].substring(0,i);
            }
        }
        return strs[0];
    }
}