2019-2020 ICPC, Asia Jakarta Regional Contest (Online Mirror, ICPC Rules, Teams Preferred)
- easy: ACEGHK
- medium-easy: BJL
- medium: D
- ?????: I
A.
B.
C.
- For \ (R [], C [ ] \) respectively parity segment.
- network!
D.
- Consider a sequence check, go right enumeration corresponding prefix pre, laid down corresponding suffix suf.
- Each line of stitching the middle of playing even special characters, build SA, suffix rk is able to match the pre intervals.
- The middle of each column splice connection with a special character, built in SA, can match the suffix rk is suf intervals.
- Problem into: the number of points within the rectangle.
E.
Delivery backwards launch range for each position.
F.
Tree hash
G.
- Incremental ranking as the number of new people there worse than the No. 1 player.
- Segment tree maintenance interval minimum.
H.
- The first case is squeezed within a rectangle, the area / 2 can.
- In the second case different rectangle to exchange A, B for each of A> B of the rectangle, respectively, if the two rectangles \ (A * B, * C D (A <B, C <D) \) , then the answer is \ (min (A, B) * min (C, D) \) , sorted by A, a first dimension enumeration whom stuck, find the maximum value suffix.
- Fried accuracy.
I.
So hard.
J.
- He noted that the type 3 up to place 50.
- \ (dp [i] [j ] \) represents Before considering \ (I \) positions, just put \ (J \) a type 3, type 2 up to put a few.
- Enumeration \ (i, j \) with type 1, try to replace, type 2 can be.
K.
Segment tree maintenance interval matrix multiplication. Interval modified to swap rows and rows, columns and columns.
L.
- Consider each "side" to be built case.
- "Edge" & workers bipartite graph, running match?
- Each group of workers to build an intermediate point, maximum flow, ok, less side.
- Spanning Tree how to do? How to choose a ring Long Sheung Wan - an edge?
- Build a flow restriction intermediate source point "on the side of the ring" point traffic does not exceed the loop length --1. The maximum flow for the \ (n-1 \) can.