ID NAME QUALITY USERS ACC % DIFFICULTY C I
28451 Ada and Cities   6 78
17
17
28450 Ada and Path   5 65
17
30
17261 Bank robbery   2 229
17
23
10145 Birthday Cake   6 217
13
11
1693 Coconuts   10 630
21
30
3579 Disjoint Paths   3 298
26
30
4110 Fast Maximum Flow   35 2158
25
21
373 Greedy island   3 446
30
27
962 Intergalactic Map   4 519
22
29
4206 Fast Maximum Matching   25 1607
24
20
4485 MobiZone vs VinaGone   5 275
21
34
4227 "Shortest" pair of paths   3 180
23
17
3868 Total Flow   9 1271
12
13
287 Smart Network Administrator   3 397
24
31
203 Potholers   21 1953
17
13
22379 Mobile Company 2   1 59
12
17
4457 Shopping II   3 128
17
1
377 Taxi   11 1162
13
17

#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