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Where is my seat?

Here, we are going to learn about the implementation of a coding problem where is my seat? This is competitive coding type problem. Submitted by Debasis Jana, on March 22, 2019

Problem statement:

You and your friend are deciding to go for a tour by train. But before booking the ticket of the train, your friend asks you to book a ticket in such a way that both of you sit face to face.

Seating decoration is known to you (given in the image) and you as a VIP customer are allowed to book seat number according to your choice.

After booking the ticket accordingly, your friend asks you, your seat number so that he can check which is his seat number and seat position (WS/MS/AS)?

Example:

    Input:
    You have given your seat number N

    Output:
    Print your friend's seat number and seating position
    WS: For Window Seat
    MS: For Middle Seat
    AS: For Aisle Seat

    -----------------
    Sample Input:
    57
    23

    Sample Output:
    52 AS
    14 MS

Note: Before going to solution, we recommend you to try it by yourself first...

Hint: Starting from bottom to top (1 to 6) sees the difference of opposite seat number, [11,9,7,5,3,1]

Algorithm:

    1. Take input N
    2. Switch (N%12)
        2.1     Case 1: print N+11 and "WS"
        2.2     Case 2: print N+9 and "MS"
        2.3     Case 3: print N+7 and "AS"
        2.4     Case 4: print N+5 and "AS"
        2.5     Case 5: print N+3 and "MS"
        2.6     Case 6: print N+1 and "WS"
        2.7     Case 7: print N-1 and "WS"
        2.8     Case 8: print N-3 and "MS"
        2.9     Case 9: print N-5 and "AS"
        2.10    Case 10: print N-7 and "AS"
        2.11    Case 11: print N-9 and "MS"
        2.12    Default : print N-11 and "WS" 
    3. END OF PROGRAM

Explanation:

Here we are finding mod of N (entered seat number) by 12 because there are 12 seats in a single cabin of the train. Now, if we divide it by 12 we will be able to identify each seat individually by its number, first 6 (1 to 6) are at the left side and next 6 (7 to 12) are at the right side.

For example, if N=52 then, N%12=4, so 52^nd seat will get a unique number in that particular cabin and it is at the left side.

Now, by seeing the given picture we can say that difference between seat number 1 and 12 is 11, 2 and 11 is 9 and so on, means its decreasing by two, starting from 11.

So, for seat number 4 difference will be 5, that's why the opposite seat of 52 is 52+5=57.

Similarly, for N=23, the mod value is 11, and the seat difference of the opposite seat will be 9. But in this case, we have to deduct 9 from N because N is at the right side. So, ans: is 23-9=14.

C++ implementation:

#include <bits/stdc++.h>
using namespace std;

int main(){
	int N;
	//taking your seat number
	cin>>N; 	
	
	switch(N%12)
	{			
		// Finding modulous of 12 because there are 12 seats in a cabin
		// First 6 seats are at left side and next 6 seats (7 to 12) 
		//are at right side of a cabin
		case 1: 
			cout<<N+11<<" WS";
			break;
		//if modulous is 2 then we can see that seat number is 2 
		case 2: 							
			//so here the opposite seat is at right side and 
			//seat difference is 9		
			cout<<N+9<<" MS";			
			break;		
		case 3: 
			// here seat difference is 7 and opposite 
			//side is at right side
			cout<<N+7<<" AS";			
			break;
		case 4: 
			cout<<N+5<<" AS";
			break;
		case 5: 
			cout<<N+3<<" MS";
			break;
		case 6: 
			cout<<N+1<<" WS";
			break;
		// as said above seat number from 7 to 12 are at right side
		// so opposite seat will be at left side and seat difference is 1
		case 7: 
			cout<<N-1<<" WS";
			break;
		case 8: 
			cout<<N-3<<" MS";		
			break;
		case 9: 
			cout<<N-5<<" AS";
			break;
		case 10: 
			cout<<N-7<<" AS";
			break;
		case 11:
			cout<<N-9<<" MS";
			break;
		default:
			cout<<N-11<<" WS";
			break; 
	}
	return 0;
}

Output