g0801_0900.s0874_walking_robot_simulation

Class Solution

java.lang.Object

g0801_0900.s0874_walking_robot_simulation.Solution

public class Solution
extends Object

874 - Walking Robot Simulation.

Medium

A robot on an infinite XY-plane starts at point (0, 0) facing north. The robot can receive a sequence of these three possible types of commands:

• -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, then it will instead stay in its current location and move on to the next command.

Return the maximum Euclidean distance that the robot ever gets from the origin squared (i.e. if the distance is 5_, return_ 25_)_.

Note:

• North means +Y direction.
• East means +X direction.
• South means -Y direction.
• West means -X direction.

Example 1:

Input: commands = [4,-1,3], obstacles = []

Output: 25

Explanation:

The robot starts at (0, 0):

1. Move north 4 units to (0, 4).

2. Turn right.

3. Move east 3 units to (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):

1. Move north 4 units to (0, 4).

2. Turn right.

3. Move east 1 unit and get blocked by the obstacle at (2, 4), robot is at (1, 4).

4. Turn left.

5. Move north 4 units to (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 = []

Output: 36

Explanation:

The robot starts at (0, 0):

1. Move north 6 units to (0, 6).

2. Turn right.

3. Turn right.

4. Move south 6 units to (0, 0).

The furthest point the robot ever gets from the origin is (0, 6), which squared is 6² = 36 units away.

Constraints:

• 1 <= commands.length <= 104
• commands[i] is either -2, -1, or an integer in the range [1, 9].
• 0 <= obstacles.length <= 104
• -3 * 104 <= xi, yi <= 3 * 104
• The answer is guaranteed to be less than 231.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	robotSim(int[] commands, int[][] obstacles)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

robotSim

public int robotSim(int[] commands,
                    int[][] obstacles)