class Solution { public: string longestCommonPrefix(vector &strs) { string lcp; if (strs.size() == 0) return lcp; int min_len = INT_MAX; int min_idx = 0; for (int i = 0; i < strs.size(); ++i) { auto &s = strs[i]; if (s.size() < min_len) { min_len = s.size(); min_idx = i; } } auto &smin = strs[min_idx]; for (int i = 0; i < min_len; ++i) { char c = smin[i]; int j; for (j = 0; j < strs.size(); ++j) { auto &cs = strs[j]; if (c != cs[i]) break; } if (j == strs.size()) lcp += c; else break; } return lcp; } };