九度oj 1530 最长不重复子串

原题链接：http://ac.jobdu.com/problem.php?pid=1530

字符串简单题，看似O(n^2)的复杂度10000的数据量会tle，其实最长不重复子串不超过26个嘛。。。

如下：

 1 #include<algorithm>

 2 #include<iostream>

 3 #include<cstdlib>

 4 #include<cstring>

 5 #include<cstdio>

 6 using std::max;

 7 const int Max_N = 10010;

 8 int vis[26];

 9 char buf[Max_N];

10 void solve(){

11     int i, j, ans = 0, n = strlen(buf);

12     for (i = 0; i < n - 1; i++){

13         int t = 1;

14         memset(vis, 0, sizeof(vis));

15         vis[buf[i] - 'a'] = 1;

16         for (j = i + 1; j < n; j++){

17             if (!vis[buf[j] - 'a']){

18                 vis[buf[j] - 'a'] = 1;

19                 t++;

20             } else {

21                 break;

22             }

23         }

24         ans = max(ans, t);

25     }

26     printf("%d\n", ans);

27 }

28 int main(){

29 #ifdef LOCAL

30     freopen("in.txt", "r", stdin);

31     freopen("out.txt", "w+", stdout);

32 #endif

33     while (~scanf("%s", buf)) solve();

34     return 0;

35 }

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