ID NAME QUALITY USERS ACC % DIFFICULTY C I
18164 Atoms in the Lab   32 3837
8
5
328 Bishops   83 8971
14
7
2009 Cryptography   1 142
1
34
314 Digits of e   5 3018
3
3
24 Small factorials   154 51014
15
9
6236 Matches   8 454
26
7
36563 Hard Fibonacci   8 93
19
21
2906 GCD2   60 6833
12
11
2901 One Geometry Problem   9 1826
4
13
10676 0110SS   26 1766
13
9
54 Julka   163 23328
19
6
5699 The last digit re-visited   39 7454
9
9
27068 Leaf   1 66
9
1
3932 Point Connection Game in a Circle   3 765
13
21
3970 Convert to Decimal Base System   53
17
17
16034 Minimum Number   5 495
11
1
3023 Binary multiplication   3 226
17
17
35954 New Data Type   1 122
6
6
18905 Kapti and Balu   1 39
17
17
8676 Digits of Phi (Golden Ratio)   2 294
17
17
270 Digits of Pi   13 5905
9
19
5294 Recurrence   2 259
28
17
29748 Robin Hood   37
1
1
3362 Setnja   2 244
9
17
10334 SOLDIERS   7 752
8
8
1423 Digits of SQRT(2)   6 2752
11
11
738 Another Counting Problem   1 232
1
1
71 Tree   3 454
12
9
1002 Uncle Jack   13 2969
9
8
235 Very Fast Multiplication   24 1320
26
22
6479 The Very Greatest Common Divisor   4 95
21
13
1475 Play with Digit Seven   3 129
34
14

#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