Maximilian Keßler
5c4a2bb4f7
Instead of storing a rational for evey game state, we just store how many of the factorial(draw pile size) many game states can be won. This allows us to save only one 64-bit integer per game state instead of two and thus reduces memory consumption of the program significantly. Also, this makes some computations a bit easier, since we do not have to normalize when recursing - we can just add the numbe of winnable states for each possible draw. On the other hand, this means that upon lookup, we have to normalize the stored values again to retrieve the probabilities. In particular, one needs to know what the draw pile size of the game state is in order to interpret the value of the state.
43 lines
705 B
C++
43 lines
705 B
C++
//
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// Created by maximilian on 2/9/24.
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//
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#ifndef ENDGAME_ANALYZER_FACTORIAL_H
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#define ENDGAME_ANALYZER_FACTORIAL_H
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#include <cstdint>
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namespace Factorial {
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inline std::uint64_t factorial(std::size_t n)
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{
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static const std::uint64_t table[] = {
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1,
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1 ,
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2 ,
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6 ,
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24 ,
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120 ,
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720 ,
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5040 ,
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40320 ,
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362880 ,
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3628800 ,
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39916800 ,
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479001600 ,
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6227020800 ,
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87178291200 ,
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1307674368000 ,
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20922789888000 ,
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355687428096000 ,
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6402373705728000 ,
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121645100408832000 ,
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2432902008176640000 ,
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};
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assert(n <= 20);
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return table[n];
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}
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}
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#endif //ENDGAME_ANALYZER_FACTORIAL_H
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