LeetCode: Longest Common Prefix

string.erase没掌握好，悲了个剧，2次过

 1 class Solution {

 2 public:

 3     string longestCommonPrefix(vector<string> &strs) {

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         string pre = "";

 7         if (!strs.size()) return pre;

 8         for (int i = 0; i < strs[0].size(); i++) {

 9             pre += strs[0][i];

10             int j = 1;

11             for (; j < strs.size(); j++) {

12                 if (pre != strs[j].substr(0, i+1)) break;

13             }

14             if (j != strs.size()) {

15                 pre.erase(pre.size()-1, 1);

16                 return pre;

17             }

18         }

19         return pre;

20     }

21 };

 后来写了个更加精简的代码

 1 class Solution {

 2 public:

 3     string longestCommonPrefix(vector<string> &strs) {

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         sort(strs.begin(), strs.end());

 7         string ret;

 8         if (!strs.size() || !strs[0].size()) return ret;

 9         int cur = 0;

10         while (cur < strs[0].size() && strs[0][cur] == strs[strs.size()-1][cur]) {

11             ret += strs[0][cur];

12             cur++;

13         }

14         return ret;

15     }

16 };

 C#

 1 public class Solution {

 2     public string LongestCommonPrefix(string[] strs) {

 3         Array.Sort(strs);

 4         string ans = "";

 5         if (strs.Length == 0 || strs[0].Length == 0) return ans;

 6         int cur = 0;

 7         while (cur < strs[0].Length && strs[0][cur] == strs[strs.Length-1][cur]) {

 8             ans += strs[0][cur];

 9             cur++;

10         }

11         return ans;

12     }

13 }

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