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55 lines
1.6 KiB
Plaintext
55 lines
1.6 KiB
Plaintext
1| |// compile-flags: -Zinline-mir
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2| |
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3| |use std::fmt::Display;
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4| |
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5| 1|fn main() {
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6| 1| permutations(&['a', 'b', 'c']);
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7| 1|}
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8| |
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9| |#[inline(always)]
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10| 1|fn permutations<T: Copy + Display>(xs: &[T]) {
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11| 1| let mut ys = xs.to_owned();
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12| 1| permutate(&mut ys, 0);
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13| 1|}
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14| |
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15| 16|fn permutate<T: Copy + Display>(xs: &mut [T], k: usize) {
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16| 16| let n = length(xs);
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17| 16| if k == n {
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18| 6| display(xs);
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19| 10| } else if k < n {
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20| 15| for i in k..n {
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^10
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21| 15| swap(xs, i, k);
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22| 15| permutate(xs, k + 1);
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23| 15| swap(xs, i, k);
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24| 15| }
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25| 0| } else {
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26| 0| error();
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27| 0| }
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28| 16|}
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29| |
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30| 16|fn length<T>(xs: &[T]) -> usize {
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31| 16| xs.len()
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32| 16|}
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33| |
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34| |#[inline]
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35| 30|fn swap<T: Copy>(xs: &mut [T], i: usize, j: usize) {
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36| 30| let t = xs[i];
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37| 30| xs[i] = xs[j];
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38| 30| xs[j] = t;
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39| 30|}
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40| |
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41| 6|fn display<T: Display>(xs: &[T]) {
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42| 24| for x in xs {
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^18
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43| 18| print!("{}", x);
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44| 18| }
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45| 6| println!();
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46| 6|}
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47| |
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48| |#[inline(always)]
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49| 0|fn error() {
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50| 0| panic!("error");
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51| 0|}
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