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Problem: Self Crossing

Medium
30 min
Explore how to determine if a path revisits any previously visited position by analyzing a sequence of movements on an X-Y plane. Learn to apply geometric and mathematical reasoning to detect self crossing in paths, a common coding interview problem, and implement an efficient solution.

Statement

You are given an array of integers, distance, where each element represents the length of a move you will make on an X-Y plane. You start at the origin, which is point (0,0)(0, 0), and move according to the array. Specifically, you move distance[0] meters north, distance[1] meters west, distance[2] meters south, distance[3] meters east, and continue this pattern in a counterclockwise direction. Each step follows the sequence—north, west, south, east—repeating as long as there are remaining distances in the array.

Your task is to determine whether this path crosses itself at any point. This means checking whether you revisit any previously visited position (including the origin or any other point) at any step. Return TRUE if the path intersects itself, and FALSE otherwise.

Constraints:

  • 1 \leq distance.length \leq 10310^3

  • 1 \leq distance[i] \leq 10310^3

Problem
Ask
Submissions

Problem: Self Crossing

Medium
30 min
Explore how to determine if a path revisits any previously visited position by analyzing a sequence of movements on an X-Y plane. Learn to apply geometric and mathematical reasoning to detect self crossing in paths, a common coding interview problem, and implement an efficient solution.

Statement

You are given an array of integers, distance, where each element represents the length of a move you will make on an X-Y plane. You start at the origin, which is point (0,0)(0, 0), and move according to the array. Specifically, you move distance[0] meters north, distance[1] meters west, distance[2] meters south, distance[3] meters east, and continue this pattern in a counterclockwise direction. Each step follows the sequence—north, west, south, east—repeating as long as there are remaining distances in the array.

Your task is to determine whether this path crosses itself at any point. This means checking whether you revisit any previously visited position (including the origin or any other point) at any step. Return TRUE if the path intersects itself, and FALSE otherwise.

Constraints:

  • 1 \leq distance.length \leq 10310^3

  • 1 \leq distance[i] \leq 10310^3