Package g2201_2300.s2211_count_collisions_on_a_road

Class Solution

java.lang.Object
g2201_2300.s2211_count_collisions_on_a_road.Solution
public class Solution extends Object
2211 - Count Collisions on a Road\. Medium There are `n` cars on an infinitely long road. The cars are numbered from `0` to `n - 1` from left to right and each car is present at a **unique** point. You are given a **0-indexed** string `directions` of length `n`. `directions[i]` can be either `'L'`, `'R'`, or `'S'` denoting whether the ith car is moving towards the **left** , towards the **right** , or **staying** at its current point respectively. Each moving car has the **same speed**. The number of collisions can be calculated as follows: * When two cars moving in **opposite** directions collide with each other, the number of collisions increases by `2`. * When a moving car collides with a stationary car, the number of collisions increases by `1`. After a collision, the cars involved can no longer move and will stay at the point where they collided. Other than that, cars cannot change their state or direction of motion. Return _the **total number of collisions** that will happen on the road_. **Example 1:** **Input:** directions = "RLRSLL" **Output:** 5 **Explanation:** The collisions that will happen on the road are: - Cars 0 and 1 will collide with each other. Since they are moving in opposite directions, the number of collisions becomes 0 + 2 = 2. - Cars 2 and 3 will collide with each other. Since car 3 is stationary, the number of collisions becomes 2 + 1 = 3. - Cars 3 and 4 will collide with each other. Since car 3 is stationary, the number of collisions becomes 3 + 1 = 4. - Cars 4 and 5 will collide with each other. After car 4 collides with car 3, it will stay at the point of collision and get hit by car 5. The number of collisions becomes 4 + 1 = 5. Thus, the total number of collisions that will happen on the road is 5. **Example 2:** **Input:** directions = "LLRR" **Output:** 0 **Explanation:** No cars will collide with each other. Thus, the total number of collisions that will happen on the road is 0. **Constraints:** * 1 <= directions.length <= 105 * `directions[i]` is either `'L'`, `'R'`, or `'S'`.

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • countCollisions

      public int countCollisions(String directions)