_2211. Count Collisions on a Road.md

2211. Count Collisions on a Road

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First completed : July 14, 2024

Last updated : July 14, 2024

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Related Topics : String, Stack, Simulation

Acceptance Rate : 43.96 %

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Solutions

• m2211 v1 iterative.py
• m2211 v2 mathematical.py

Python

m2211 v1 iterative.py

class Solution:
    def countCollisions(self, directions: str) -> int:
        cols = 0
        lCounter = 0
        last = 'R'

        for c in reversed(directions) :
            if c == 'L' :
                lCounter += 1
                last = c

            elif c == 'S' :
                cols += lCounter
                lCounter = 0
                last = c

            elif c == 'R' and last != 'R' : # R
                cols += lCounter + 1
                lCounter = 0
                last = 'S'

        return cols

m2211 v2 mathematical.py

class Solution:
    def countCollisions(self, directions: str) -> int:
        directions = directions.lstrip('L').rstrip('R')
        return len(directions) - directions.count('S')