Fast long integers

Python’s long integers are surprisingly fast, so if you want to add a value of 10^100 at most 1000 times, it’s faster to calculate it as it is without removing the remainder each time. python

In [27]: timeit
    ...: x = int("7" * 100)
    ...: for i in range(1000):
    ...:     x += x
    ...:     x %= 1000000007
    ...: 
104 µs ± 890 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)

• In ABC177, the code that computes without taking the remainder each time and takes the remainder at the end was the fastest in the PyPy3 submission
  • This problem was 10^9 times 10^6 additive multiplications at the highest, and the maximum could fit into about 10^30.

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