A robot on an infinite XY-plane starts at point (0, 0) facing north. The robot receives an array of integers commands, which represents a sequence of moves that it needs to execute. There are only three possible types of instructions the robot can receive:
-2: Turn left 90 degrees.-1: Turn right 90 degrees.1 <= k <= 9: Move forward k units, one unit at a time.Some of the grid squares are obstacles. The ith obstacle is at grid point obstacles[i] = (xi, yi). If the robot runs into an obstacle, it will stay in its current location (on the block adjacent to the obstacle) and move onto the next command.
Return the maximum squared Euclidean distance that the robot reaches at any point in its path (i.e. if the distance is 5, return 25).
Note:
(0, 0). If this happens, the robot will ignore the obstacle until it has moved off the origin. However, it will be unable to return to (0, 0) due to the obstacle.
Example 1:
Input: commands = [4,-1,3], obstacles = []
Output: 25
Explanation:
The robot starts at (0, 0):
(0, 4).(3, 4).The furthest point the robot ever gets from the origin is (3, 4), which squared is 32 + 42 = 25 units away.
Example 2:
Input: commands = [4,-1,4,-2,4], obstacles = [[2,4]]
Output: 65
Explanation:
The robot starts at (0, 0):
(0, 4).(2, 4), robot is at (1, 4).(1, 8).The furthest point the robot ever gets from the origin is (1, 8), which squared is 12 + 82 = 65 units away.
Example 3:
Input: commands = [6,-1,-1,6], obstacles = [[0,0]]
Output: 36
Explanation:
The robot starts at (0, 0):
(0, 6).(0,0), robot is at (0, 1).The furthest point the robot ever gets from the origin is (0, 6), which squared is 62 = 36 units away.
Constraints:
1 <= commands.length <= 104commands[i] is either -2, -1, or an integer in the range [1, 9].0 <= obstacles.length <= 104-3 * 104 <= xi, yi <= 3 * 104231.Simulate the movement of the robot by maintaining a variable for the current direction. Use an array to store the possible directions: north, east, south, and west. When a turn command is received, adjust the direction index. For movement commands, move the robot in the direction indexed by the current direction.
The solution defines the possible directions the robot can face using two arrays dx and dy. The direction is managed using a variable that cycles through the indices on executing turn commands. By maintaining a set of obstacles, it ensures efficient checks when the robot moves. The maximum squared distance is updated whenever the robot's position changes.
C++
Java
JavaScript
Time Complexity: O(N + M), where N is the number of commands and M is the number of obstacles.
Space Complexity: O(M), where M is the number of obstacles.
Walking Robot Simulation - Leetcode 874 - Python • NeetCodeIO • 11,018 views views
Watch 9 more video solutions →Practice Walking Robot Simulation with our built-in code editor and test cases.
Practice on FleetCodePractice this problem
Open in Editor