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28 lines
694 B
Rust
28 lines
694 B
Rust
use std::ops::Range;
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trait Itble<'r, T, I: Iterator<Item=T>> { fn iter(&'r self) -> I; }
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impl<'r> Itble<'r, usize, Range<usize>> for (usize, usize) {
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fn iter(&'r self) -> Range<usize> {
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let &(min, max) = self;
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min..max
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}
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}
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fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
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{
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let cont_iter = cont.iter();
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//~^ ERROR explicit lifetime required in the type of `cont` [E0621]
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let result = cont_iter.fold(Some(0), |state, val| {
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state.map_or(None, |mask| {
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let bit = 1 << val;
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if mask & bit == 0 {Some(mask|bit)} else {None}
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})
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});
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result.is_some()
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}
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fn main() {
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check(&(3, 5));
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}
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