【Leetcode】Longest Common Prefix

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

class Solution {
public:
    string longestCommonPrefix(vector<string> &strs) {
        string prefix;
        int size = strs.size();
        bool flag = true;
        if (size != 0) {
            for (int i = 0; i < strs[0].size() && flag; ++i) {
                for (int j = 1; j < size; ++j) {
                    if (strs[j][i] != strs[0][i]) {
                        flag = false;
                        break;
                    }   
                }
                if (flag) {
                    prefix += strs[0][i];
                }
            }
        }
        return prefix;
    }
};