ID NAME QUALITY USERS ACC % DIFFICULTY C I
28451 Ada and Cities   9 94
19
17
28450 Ada and Path   7 74
15
28
17261 Bank robbery   2 233
17
23
10145 Birthday Cake   7 227
13
12
1693 Coconuts   12 645
21
28
3579 Disjoint Paths   4 305
24
27
4110 Fast Maximum Flow   39 2246
25
21
373 Greedy island   4 458
28
26
962 Intergalactic Map   4 526
22
29
4206 Fast Maximum Matching   24 1668
24
20
4485 MobiZone vs VinaGone   6 284
20
31
4227 "Shortest" pair of paths   3 182
23
17
3868 Total Flow   12 1291
14
12
287 Smart Network Administrator   3 401
24
31
203 Potholers   22 2002
17
12
22379 Mobile Company 2   2 61
13
17
4457 Shopping II   3 129
17
1
377 Taxi   14 1187
13
16

#max-flow

The problem involves maximum flow problem

https://en.wikipedia.org/wiki/Maximum_flow_problem http://www.cs.princeton.edu/courses/archive/spr04/cos226/lectures/maxflow.4up.pdf