ID NAME QUALITY USERS ACC % DIFFICULTY C I
28451 Ada and Cities   10 142
19
17
28450 Ada and Path   8 103
15
28
17261 Bank robbery   3 246
17
21
10145 Birthday Cake   7 255
12
12
1693 Coconuts   13 948
21
28
3579 Disjoint Paths   4 312
24
27
4110 Fast Maximum Flow   48 2885
25
22
373 Greedy island   6 510
26
26
962 Intergalactic Map   2 564
19
28
4206 Fast Maximum Matching   30 1987
22
19
4485 MobiZone vs VinaGone   7 322
17
31
4227 "Shortest" pair of paths   3 211
23
17
3868 Total Flow   11 1387
14
13
287 Smart Network Administrator   3 451
23
28
203 Potholers   22 2270
16
12
22379 Mobile Company 2   2 69
13
17
4457 Shopping II   3 147
17
1
377 Taxi   14 1237
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