LA 1262

Problem Number - Problem Name
1262 - Password

Explanation
The solution for this problem consists of 2 phases. 1. Extracting the characters that form possible combinations. 2. Sort possible combinations and get the kth password in the list.

Gotchas
Eliminate the redundant answers from the list while sorting.

Implementations
For each row in the two grid, create a set of the intersection between the 2 rows, e.g. if the input was: AYGSU DOMRA CPFAS XBODG WDYPK PRXWO CBOPT DOSBG GTRAR APMMS WSXNU EFGHI Then the constructed sets should be: ADCW OPB GMOX AP USG Were each line is the intersection of 2 rows with the same index in input. Then we sort these sets. ACDW BOP GMOX AP GSU Finally we get the kth element by having 5 nested loops creating the all possible combinations in lexicographic order, notice that the nested loops approach is not bad as it sounds since the worst case will be 6^5 = 7776 possible iterations. Instead of creating all possible combinations we can create only the kth combination by counting number of iterations in the inner loop, then generating the resulting password.

Input
3 1 AYGSU DOMRA CPFAS XBODG WDYPK PRXWO CBOPT DOSBG GTRAR APMMS WSXNU EFGHI 5 AYGSU DOMRA CPFAS XBODG WDYPK PRXWO CBOPT DOSBG GTRAR APMMS WSXNU EFGHI 64 FGHIJ EFGHI DEFGH CDEFG BCDEF ABCDE WBXDY UWYXZ XXZFG YYFYH EZWZI ZGHIJ

Output
ABGAG ABGPS NO