ID NAME QUALITY USERS ACC % DIFFICULTY C I
18164 Atoms in the Lab   32 3843
8
5
328 Bishops   83 8986
14
7
2009 Cryptography   1 142
1
34
314 Digits of e   5 3026
3
3
24 Small factorials   154 51307
15
9
6236 Matches   8 458
26
7
36563 Hard Fibonacci   8 92
19
21
2906 GCD2   60 6865
12
11
2901 One Geometry Problem   9 1827
4
13
10676 0110SS   26 1770
13
9
54 Julka   165 23406
19
6
5699 The last digit re-visited   39 7461
9
9
27068 Leaf   1 66
9
1
3932 Point Connection Game in a Circle   3 767
13
21
3970 Convert to Decimal Base System   56
17
17
16034 Minimum Number   5 497
11
1
3023 Binary multiplication   3 229
17
17
35954 New Data Type   1 123
6
6
18905 Kapti and Balu   1 41
17
17
8676 Digits of Phi (Golden Ratio)   3 295
9
9
270 Digits of Pi   13 5914
9
19
5294 Recurrence   2 262
28
17
29748 Robin Hood   37
1
1
3362 Setnja   2 249
9
17
10334 SOLDIERS   7 754
8
8
1423 Digits of SQRT(2)   6 2759
11
11
738 Another Counting Problem   1 235
1
1
71 Tree   3 463
12
9
1002 Uncle Jack   13 2969
9
8
235 Very Fast Multiplication   25 1359
25
21
6479 The Very Greatest Common Divisor   4 95
21
13
1475 Play with Digit Seven   3 136
28
12

#big-numbers

The problem involves arbitrary precision arithmetic

https://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic https://en.wikipedia.org/wiki/Karatsuba_algorithm - efficient multiplication algorithm https://en.wikipedia.org/wiki/Toom%E2%80%93Cook_multiplication - as above https://en.wikipedia.org/wiki/Sch%C3%B6nhage%E2%80%93Strassen_algorithm - as above https://en.wikipedia.org/wiki/F%C3%BCrer%27s_algorithm - as above