[LeetCode] #14 Longest Common Prefix

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

 本题寻找一组字符串的公共前缀，只需要查询较短子串前n个字符是否相等。时间：8ms

代码如下：

class Solution {
public:
    string longestCommonPrefix(vector<string>& strs) {
        if (strs.size() == 0)
            return "";
        string str = strs[0];
        for (int i = 1; i < strs.size(); i++){
            if (strs[i].size() == 0 || str.size() == 0)
                return "";
            int n = (str.size()<strs[i].size() ?str.size():strs[i].size());
            int j = 0;
            for (; j < n; j++){
                if (str[j] != strs[i][j])
                    break;
            };
            str = str.substr(0, j);
        }
        return str;
    }
};