Meaning of the questions: http://acm.hdu.edu.cn/showproblem.php?pid=3336
rt
Ideas: https://www.cnblogs.com/Tree-dream/p/7443897.html
Almost, dp recursive just simplify it.
1 #define IOS ios_base::sync_with_stdio(0); cin.tie(0); 2 #include <cstdio>//sprintf islower isupper 3 #include <cstdlib>//malloc exit strcat itoa system("cls") 4 #include <iostream>//pair 5 #include <fstream>//freopen("C:\\Users\\13606\\Desktop\\Input.txt","r",stdin); 6 #include <bitset> 7 //#include <map> 8 //#include<unordered_map> 9 #include <vector> 10 #include <stack> 11 #include <set> 12 #include <string.h>//strstr substr strcat 13 #include <string> 14 #include <time.h>// srand(((unsigned)time(NULL))); Seed n=rand()%10 - 0~9; 15 #include <cmath> 16 #include <deque> 17 #include <queue>//priority_queue<int, vector<int>, greater<int> > q;//less 18 #include <vector>//emplace_back 19 //#include <math.h> 20 #include <cassert> 21 #include <iomanip> 22 //#include <windows.h>//reverse(a,a+len);// ~ ! ~ ! floor 23 #include <algorithm>//sort + unique : sz=unique(b+1,b+n+1)-(b+1);+nth_element(first, nth, last, compare) 24 using namespace std;//next_permutation(a+1,a+1+n);//prev_permutation 25 //****************** 26 clock_t __START,__END; 27 double __TOTALTIME; 28 void _MS(){__START=clock();} 29 void _ME(){__END=clock();__TOTALTIME=(double)(__END-__START)/CLOCKS_PER_SEC;cout<<"Time: "<<__TOTALTIME<<" s"<<endl;} 30 //*********************** 31 #define rint register int 32 #define fo(a,b,c) for(rint a=b;a<=c;++a) 33 #define fr(a,b,c) for(rint a=b;a>=c;--a) 34 #define mem(a,b) memset(a,b,sizeof(a)) 35 #define pr printf 36 #define sc scanf 37 #define ls rt<<1 38 #define rs rt<<1|1 39 typedef pair<int,int> PII; 40 typedef vector<int> VI; 41 typedef unsigned long long ull; 42 typedef long long ll; 43 typedef double db; 44 const db E=2.718281828; 45 const db PI=acos(-1.0); 46 const ll INF=(1LL<<60); 47 const int inf=(1<<30); 48 const db ESP=1e-9; 49 const int MOD = ( int ) 1E9 + . 7 ; 50 const int N = ( int ) 1e6 + 10 ; 51 is 52 is int the Next [N], LenB; 53 is char B [N]; 54 is 55 void set_naxt () // substring the next array: the longest prefix and a suffix of the longest string of the same length 56 is { 57 is int I = 0 , J = - . 1 ; 58 the next [ 0 ] = - . 1 ; // initialize to -1 does not exist the same longest prefix and suffix maximum 59 the while (I < LenB) 60 { 61 is IF (j == - . 1 || B [I] == B [j]) 62 is { 63 is I ++ ; 64 j ++ ; 65 the Next [I] = j; // the j (same maximum prefix length and the maximum suffix) assigned Next [I] 66 } 67 the else 68 J = the Next [J]; // Previous retrospective 69 } 70 } 71 is int DP [N]; 72 73 is void Solve () 74 { 75 sc("%d",&lenb); 76 sc("%s",b); 77 b[lenb++]='%'; 78 fo(i,0,lenb)dp[i]=0; 79 set_naxt(); 80 int ans=0; 81 for(int i=1;i<lenb;++i) 82 dp[i]=dp[Next[i]]+1,ans+=dp[i],ans%=10007; 83 pr("%d\n",ans); 84 } 85 86 int main() 87 { 88 int T; 89 sc("%d",&T); 90 while(T--)solve(); 91 return 0; 92 } 93 94 /**************************************************************************************/