编写一个函数来查找字符串数组中的最长公共前缀，保证存在。c➕➕，不用容器

#include <iostream>
#include <vector>
#include <string>
using namespace std;

string longestCommonPrefix(vector<string>& strs) {
    string res = "";
    if (strs.empty()) return res;
    int len = strs[0].size();
    for (int i = 0; i < len; i++) {
        char c = strs[0][i];
        for (int j = 1; j < strs.size(); j++) {
            if (i >= strs[j].size() || strs[j][i] != c) {
                return res;
            }
        }
        res += c;
    }
    return res;
}

int main() {
    vector<string> strs = {"flower", "flow", "flight"};
    string res = longestCommonPrefix(strs);
    cout << res << endl;
    return 0;
}