We treat arrival and departure events as points on a timeline. By sorting both arrays, we can use two pointers to count how many trains are in the station at any point. When a train arrives, we increase the platform count; when a train departs, we decrease it.

1. Sort both arrival and departure arrays.
2. Initialize platforms_needed = 0, max_platforms = 0.
3. Initialize two pointers: i = 0 (for arrival) and j = 0 (for departure).
4. While i < n:
   • If arrival[i] <= departure[j]:
     • platforms_needed += 1
     • Update max_platforms = max(max_platforms, platforms_needed)
     • i += 1
   • Else:
     • platforms_needed -= 1
     • j += 1
5. Return max_platforms.

• Time Complexity: O(N log N) because of sorting.
• Space Complexity: O(1), assuming sorting is in-place or ignoring it.

def min_platforms(arrival, departure):
    arrival.sort()
    departure.sort()
    
    n = len(arrival)
    i, j = 0, 0
    platforms_needed = 0
    max_platforms = 0
    
    while i < n:
        # If train is arriving before or at the time another train departs
        if arrival[i] <= departure[j]:
            platforms_needed += 1
            max_platforms = max(max_platforms, platforms_needed)
            i += 1
        else:
            # Train departed, platform free
            platforms_needed -= 1
            j += 1
            
    return max_platforms