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Update to new for-loop protocol

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This commit is contained in:
Corey Richardson 2013-05-16 22:57:49 -04:00
parent c67a85ada1
commit af54d58891
1 changed files with 4 additions and 4 deletions
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8
src/libcore/vec.rs
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@ -1790,23 +1790,23 @@ pub fn each2_mut<U, T>(v1: &mut [U], v2: &mut [T], f: &fn(u: &mut U, t: &mut T)
*
* * `fun` - The function to iterate over the combinations
*/
pub fn each_permutation<T:Copy>(values: &[T], fun: &fn(perm : &[T]) -> bool) {
pub fn each_permutation<T:Copy>(values: &[T], fun: &fn(perm : &[T]) -> bool) -> bool {
let length = values.len();
let mut permutation = vec::from_fn(length, |i| values[i]);
if length <= 1 {
fun(permutation);
return;
return true;
}
let mut indices = vec::from_fn(length, |i| i);
loop {
if !fun(permutation) { return; }
if !fun(permutation) { return true; }
// find largest k such that indices[k] < indices[k+1]
// if no such k exists, all permutations have been generated
let mut k = length - 2;
while k > 0 && indices[k] >= indices[k+1] {
k -= 1;
}
if k == 0 && indices[0] > indices[1] { return; }
if k == 0 && indices[0] > indices[1] { return true; }
// find largest l such that indices[k] < indices[l]
// k+1 is guaranteed to be such
let mut l = length - 1;