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 };

 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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