Zjut practice 3.3 K-K Problem B. last digit

Problem B. last digit

Background

Give you a integer number N (1 <= n <= 2*10100). Please compute

S = 11 + 22 + 33 +... + NN

Give the last digit of S to me.

Input

Input File consists of several NS, each n a line. It is ended with n = 0.

Output

For each n give a line containing only one digit, which is the last digit of S.

Sample Input

1

2

3

0

Sample output

1

5

2

 

# Include <iostream> # Include < String > Using   Namespace  STD;  Const   Int Maxn = 101  ;  Int  Sum [maxn];  Int Myfun (Int  N ){  Int Ans = 1  ;  Int Len = n % 100  ; N = N % 10  ;  For ( Int I = 1 ; I <= Len; I ++ ) Ans = (ANS * n) % 10 ;  Return  Ans ;}  Int  Main (){  For ( Int I = 1 ; I <= 100 ; I ++ ) Sum [I] = (Sum [I- 1 ] + Myfun (I) % 10  ;  String  S; While (CIN> S & S [ 0 ]! = '  0  '  ){  Int  N;  If (S. Length ()> = 2  ) N = S [S. Length ()- 1 ]- '  0  ' +10 * (S [S. Length ()- 2 ]- '  0  '  );  Else  N = S [S. Length ()- 1 ]- '  0  '  ; Cout <Sum [N] < "  \ N "  ;}} 

Simple simulation with a cycle of 100.