ArrayManipulation.rb

=begin
Starting with a 1-indexed array of zeros and a list of operations, for each operation add a value to each the array element between two given indices, inclusive. Once all operations have been performed, return the maximum value in the array.

Example


Queries are interpreted as follows:

    a b k
    1 5 3
    4 8 7
    6 9 1
Add the values of  between the indices  and  inclusive:

index->	 1 2 3  4  5 6 7 8 9 10
	[0,0,0, 0, 0,0,0,0,0, 0]
	[3,3,3, 3, 3,0,0,0,0, 0]
	[3,3,3,10,10,7,7,7,0, 0]
	[3,3,3,10,10,8,8,8,1, 0]
The largest value is  after all operations are performed.

Function Description

Complete the function arrayManipulation in the editor below.

arrayManipulation has the following parameters:

int n - the number of elements in the array
int queries[q][3] - a two dimensional array of queries where each queries[i] contains three integers, a, b, and k.
Returns

int - the maximum value in the resultant array
Input Format

The first line contains two space-separated integers  and , the size of the array and the number of operations.
Each of the next  lines contains three space-separated integers ,  and , the left index, right index and summand.

Constraints

Sample Input

5 3
1 2 100
2 5 100
3 4 100
Sample Output

200
Explanation

After the first update the list is 100 100 0 0 0.
After the second update list is 100 200 100 100 100.
After the third update list is 100 200 200 200 100.

The maximum value is .
=end

def arrayManipulation(n, queries)
    # Write your code here
    max    = 0
    a      = [0]*n
    queries.each do |x|
      a[x[0] -1] += x[2]
      a[x[1]] -= x[2] if x[1] < n
    end
    sum = 0
    a.each do |val|
      sum += val
      max = sum if sum > max
    end
  return max
end

n = 5
queries = [[1, 2, 100], 
           [2, 5, 100], 
           [3, 4, 100]]

# n = 10
# queries = [[1, 5, 3], 
#            [2, 5, 100], 
#            [3, 4, 100]]
p arrayManipulation(n, queries)