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Problem · Intervals

Obstacle Placement Queries

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Problem statement

A special thank-you to the friend who kindly shared that this problem was seen again on August 4, 2026! ദ്ദി(ᵔᗜᵔ)

You are given an infinite number line and an array operations. Process the operations in order while maintaining the coordinates that contain obstacles.

  • [1, x]: Place an obstacle at coordinate x. Coordinate x is guaranteed to contain no obstacle when this operation is performed.
  • [2, x, size]: Check whether a block of length size can end immediately before coordinate x. The block would occupy every integer coordinate from x - size through x - 1. Append '1' to the answer if none of those coordinates contains an obstacle; otherwise append '0'. This operation only checks feasibility and does not place the block.

Return the binary string formed by the results of all type-2 operations in their original order.

Function

obstaclePlacementQueries(operations: int[][]) → String

Examples

Example 1

operations = [[2, 0, 2], [1, 1], [2, 0, 2], [2, 2, 2]]return = "110"
  1. [2, 0, 2] checks coordinates -2 and -1. There are no obstacles, so append 1.
  2. [1, 1] places an obstacle at coordinate 1.
  3. [2, 0, 2] still checks coordinates -2 and -1. Both are free, so append 1.
  4. [2, 2, 2] checks coordinates 0 and 1. Coordinate 1 contains an obstacle, so append 0.

More Capital One problems

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public String obstaclePlacementQueries(int[][] operations) {
  // write your code here
}
operations[[2, 0, 2], [1, 1], [2, 0, 2], [2, 2, 2]]
expected"110"
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