Range Update Point Query

Problem

Start with an array of n zeros and process operations: [1, left, right, value] adds value to every index in the inclusive range, and [2, index] asks for the current value at an index. Return the query results in order.

Use a difference array where a range update touches only two positions, and a query takes the prefix sum. Values may be negative.

Hint

Adding val at left and subtracting it at right + 1 makes the prefix sum apply the range.

Test cases

case 1

in: [5,[[1,1,3,2],[2,0],[2,2],[1,0,2,1],[2,1],[2,4]]]

expected: [0,2,3,0]

case 2

in: [1,[[2,0]]]

expected: [0]

case 3

in: [3,[]]

expected: []

case 4

in: [2,[[1,0,1,5],[2,1],[1,0,0,-5],[2,0]]]

expected: [5,0]

Starter codePython

def range_update_point_query(n, operations):
    # Your code here
    pass

4 test cases · run your code against them in the editor