How to Solve Robot Collisions Leetcode Problem - Interview Coder Guide
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How to Solve Robot Collisions Problem

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Hard#2846
LeetCode Problem

Robot Collisions

There are n 1-indexed robots, each having a position on a line, health, and movement direction. You are given 0-indexed integer arrays positions, healths, and a string directions (directions[i] is eit...

ArrayStackSorting+1 more

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Problem Breakdown

Understanding the Robot Collisions Problem

Let's break down this LeetCode problem and understand what makes it challenging in interview settings.

Problem Statement

There are n 1-indexed robots, each having a position on a line, health, and movement direction. You are given 0-indexed integer arrays positions, healths, and a string directions (directions[i] is either 'L' for left or 'R' for right). All integers in positions are unique. All robots start moving on the line simultaneously at the same speed in their given directions. If two robots ever share the same position while moving, they will collide. If two robots collide, the robot with lower health is removed from the line, and the health of the other robot decreases by one. The surviving robot continues in the same direction it was going. If both robots have the same health, they are both removed from the line. Your task is to determine the health of the robots that survive the collisions, in the same order that the robots were given, i.e. final health of robot 1 (if survived), final health of robot 2 (if survived), and so on. If there are no survivors, return an empty array. Return an array containing the health of the remaining robots (in the order they were given in the input), after no further collisions can occur. Note: The positions may be unsorted.

HardProblem #2846
LeetCode

Robot Collisions

Related Topics
ArrayStackSortingSimulation
How Interview Coder Helps

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Examples

Example 1
INPUT
positions = [5,4,3,2,1], healths = [2,17,9,15,10], directions = "RRRRR"
OUTPUT
[2,17,9,15,10]
EXPLANATION

No collision occurs in this example, since all robots are moving in the same direction. So, the health of the robots in order from the first robot is returned, [2, 17, 9, 15, 10].

Example 2
INPUT
positions = [3,5,2,6], healths = [10,10,15,12], directions = "RLRL"
OUTPUT
[14]
EXPLANATION

There are 2 collisions in this example. Firstly, robot 1 and robot 2 will collide, and since both have the same health, they will be removed from the line. Next, robot 3 and robot 4 will collide and since robot 4's health is smaller, it gets removed, and robot 3's health becomes 15 - 1 = 14. Only robot 3 remains, so we return [14].

Example 3
INPUT
positions = [1,2,5,6], healths = [10,10,11,11], directions = "
OUTPUT
Example output

Constraints

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Frequently Asked Questions

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