IOI '14 P2 - Wall
View as PDFJian-Jia is building a wall by stacking bricks of the same size together. This wall consists of  columns of bricks, which are numbered 
 to 
 from left to right. The columns may have different heights. The height of a column is the number of bricks in it.
Jian-Jia builds the wall as follows. Initially there are no bricks in any column. Then, Jian-Jia goes through  phases of adding or removing bricks. The building process completes when all 
 phases are finished. In each phase Jian-Jia is given a range of consecutive brick columns and a height 
, and he does the following procedure:
- In an adding phase, Jian-Jia adds bricks to those columns in the given range that have less than 
bricks, so that they have exactly
bricks. He does nothing on the columns having
or more bricks.
 - In a removing phase, Jian-Jia removes bricks from those columns in the given range that have more than 
bricks, so that they have exactly
bricks. He does nothing on the columns having
bricks or less.
 
Your task is to determine the final shape of the wall.
Example
We assume that there are  brick columns and 
 wall building phases. All ranges in the following table are inclusive. Diagrams of the wall after each phase are shown below.
| phase | type | range | height | 
|---|---|---|---|
| 0 | add | columns  | 
|
| 1 | remove | columns  | 
|
| 2 | remove | columns  | 
|
| 3 | add | columns  | 
|
| 4 | add | columns  | 
|
| 5 | remove | columns  | 
Since all columns are initially empty, after phase  each of the columns 
 to 
 will have 
 bricks.
Columns 
 and 
 remain empty. In phase 
, the bricks are removed from columns 
 to 
 until each of
them has 
 brick, and column 
 remains empty. Columns 
 to 
, which are out of the given range,
remain unchanged. Phase 
 makes no change since columns 
 to 
 do not have more than 
 bricks.
After phase 
 the numbers of bricks in columns 
, 
, and 
 increase to 
. There are 
 bricks in column
 after phase 
. Phase 
 removes all bricks from columns 
 and 
.
Given the description of the  phases, please calculate the number of bricks in each column after all phases are finished. You need to implement the function 
buildWall.
buildWall(n, k, op, left, right, height, finalHeight)n: the number of columns on the wall.k: the number of phases.op: array of length;
op[i]is the type of phase:
for an adding phase and
for a removing phase, for
.
leftandright: arrays of length; the range of columns in phase
starts with column
left[i]and ends with columnright[i](including endpointsleft[i]andright[i]), for. You will always have
left[i]right[i].height: array of lengthk;height[i]is the height parameter of phase, for
.
finalHeight: array of length; you should return your results by placing the final number of bricks in column
into
finalHeight[i], for.
Subtasks
For all subtasks the height parameters of all phases are nonnegative integers less or equal to .
| subtask | points | note | ||
|---|---|---|---|---|
| 1 | 8 | no additional limits | ||
| 2 | 24 | all adding phases are before all removing phases | ||
| 3 | 29 | no additional limits | ||
| 4 | 39 | no additional limits | 
Implementation details
Your submission should implement the subprogram described above using the following signatures.
void buildWall(int n, int k, int op[], int left[], int right[], int height[], int finalHeight[]);
Comments
that's a pretty long wall
who's gonna pay for it?
MEXICOOOOO!