Make partition_point to forward to binary_search_by

This commit is contained in:
VillSnow 2021-05-17 19:13:41 +09:00
parent 3396a383bb
commit 5db13c529c

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@ -3458,27 +3458,7 @@ impl<T> [T] {
where
P: FnMut(&T) -> bool,
{
let mut left = 0;
let mut right = self.len();
while left != right {
let mid = left + (right - left) / 2;
// SAFETY: When `left < right`, `left <= mid < right`.
// Therefore `left` always increases and `right` always decreases,
// and either of them is selected. In both cases `left <= right` is
// satisfied. Therefore if `left < right` in a step, `left <= right`
// is satisfied in the next step. Therefore as long as `left != right`,
// `0 <= left < right <= len` is satisfied and if this case
// `0 <= mid < len` is satisfied too.
let value = unsafe { self.get_unchecked(mid) };
if pred(value) {
left = mid + 1;
} else {
right = mid;
}
}
left
self.binary_search_by(|x| if pred(x) { Less } else { Greater }).unwrap_or_else(|i| i)
}
}