HDU 3336 Count the String（KMP+DP）

 1 #include<iostream> 
 2 #include<cstring>
 3 using namespace std;
 4 
 5 const int maxn = 200000 + 5;
 6 
 7 int n;
 8 
 9 char a[maxn];
10 int next[maxn];
11 int dp[maxn];
12 
13 void get_next()
14 {
15     int i = -1, j = 0;
16     ::next[0] = -1;
17     int l = strlen(a);
18     while (j < l)
19     {
20         if (i == -1 || a[i] == a[j])
21             ::next[++j] = ++i;
22         else
23             i = ::next[i];
24     }
25 }
26 
27 int main()
28 {
29     //freopen("D:\\txt.txt", "r", stdin);
30     int t;
31     cin >> t;
32     while (t--)
33     {
34         cin >> n;
35         cin >> a;
36         get_next();
37         memset(dp, 1, sizeof(dp));
38         dp[0] = 0;
39         int sum = 0;
40         for (int i = 1; i <= n; i++)
41         {
42             dp[i] = dp[::next[i]] + 1;
43             sum += dp[i] % 10007;
44         }
45         cout << sum % 10007 << endl;
46     }
47     return 0;
48 }