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  1. #include <stdlib.h>
  2. #include <stdio.h>
  3.  
  4. int** N;
  5.  
  6. void prepare()
  7. {
  8.     int i;
  9.     N = malloc(9 * sizeof(int*));
  10.     for (i = 1; i <= 8; i++)
  11.     {
  12.         int length = i * 9 + 1;
  13.         N[i] = malloc(length * sizeof(int));
  14.  
  15.         if (i == 1)
  16.         {
  17.             int j;
  18.             for (j = 0; j < length; j++)
  19.                 N[i][j] = 1;
  20.         }
  21.         else
  22.         {
  23.             int runningsum = 0;
  24.             int k = 0;
  25.             for ( ; k <= length / 2; k++)
  26.             {
  27.                 runningsum += N[i-1][k];
  28.                 if (k >= 10)
  29.                    runningsum -= N[i-1][k-10];
  30.                 N[i][k] = runningsum;
  31.             }
  32.             for ( ; k < length; k++)
  33.             {
  34.                 N[i][k] = N[i][length - 1 - k];
  35.             }
  36.         }
  37.     }
  38. }
  39.  
  40. static unsigned long long l_t(size_t digits)
  41. {
  42.     unsigned long long tickets = 0;
  43.     size_t i = 0;
  44.  
  45.     for( ; i <= (digits*9); i++ )
  46.     {
  47.         unsigned long long n = N[digits][i];
  48.         tickets += n*n;
  49.     }
  50.     return tickets;
  51. }
  52.  
  53. int main()
  54. {
  55.     prepare();
  56.     printf
  57.     (
  58.         "1: %llu\n2: %llu\n3: %llu\n4: %llu\n5: %llu\n6: %llu\n7: %llu\n8: %llu\n", 
  59.         l_t(1),l_t(2),l_t(3),l_t(4),l_t(5),l_t(6),l_t(7),l_t(8)
  60.     );
  61.     return 0;
  62. }
  63.  
Success #stdin #stdout 0s 1920KB
comments (?)
stdin
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Standard input is empty
stdout
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1: 10
2: 670
3: 55252
4: 4816030
5: 432457640
6: 39581170420
7: 3671331273480
8: 343900019857310
https://ideone.com/FVNJdH
language:
C99 (gcc 8.3)
created:
11 years ago
visibility:
public

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