LeetCode: Longest Common Prefix

string.erase没掌握好，悲了个剧，2次过

class Solution {
public:
    string longestCommonPrefix(vector<string> &strs) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        string pre = "";
        if (!strs.size()) return pre;
        for (int i = 0; i < strs[0].size(); i++) {
            pre += strs[0][i];
            int j = 1;
            for (; j < strs.size(); j++) {
                if (pre != strs[j].substr(0, i+1)) break;
            }
            if (j != strs.size()) {
                pre.erase(pre.size()-1, 1);
                return pre;
            }
        }
        return pre;
    }
};

 后来写了个更加精简的代码

class Solution {
public:
    string longestCommonPrefix(vector<string> &strs) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        sort(strs.begin(), strs.end());
        string ret;
        if (!strs.size() || !strs[0].size()) return ret;
        int cur = 0;
        while (cur < strs[0].size() && strs[0][cur] == strs[strs.size()-1][cur]) {
            ret += strs[0][cur];
            cur++;
        }
        return ret;
    }
};

 C#

public class Solution {
    public string LongestCommonPrefix(string[] strs) {
        Array.Sort(strs);
        string ans = "";
        if (strs.Length == 0 || strs[0].Length == 0) return ans;
        int cur = 0;
        while (cur < strs[0].Length && strs[0][cur] == strs[strs.Length-1][cur]) {
            ans += strs[0][cur];
            cur++;
        }
        return ans;
    }
}