A Compiler Mystery: We are given a C-language style for loop of type
for (variable = A; variable != B; variable += C) statement;
I.e., a loop which starts by setting variable to value A and while variable
is not equal to B, repeats statement followed by increasing the variable by C.
We want to know how many times does the statement get executed for particular
values of A, B and C, assuming that all arithmetics is calculated in a k-bit
unsigned integer type (with values
0 <= x < 2k) modulo 2k.
The input consists of several instances. Each instance is described by a single
line with four integers A, B, C, k separated by a single space.
The integer k (1 <= k <= 32) is the number of bits of the control
variable of the loop and A, B, C (0 <= A, B, C < 2k) are the
parameters of the loop.
The input is finished by a line containing four zeros.
The output consists of several lines corresponding to the instances on the input.
The i-th line contains either the number of executions of the statement
in the i-th instance (a single integer number) or the word FOREVER
if the loop does not terminate.
3 3 2 16 3 7 2 16 7 3 2 16 3 4 2 16 0 0 0 0
0 2 32766 FOREVER
Migrated from old NTUJ.
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