ajinkya/pathfinder2
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Fix computation of simplifications.

Browse source
This commit is contained in:
chriseth 2022-12-21 15:15:42 +01:00
parent 4171afe31e
commit b3e8914c5c
1 changed files with 16 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
src/graph/flow.rs
View file

@ -456,35 +456,29 @@ fn next_full_capacity_edge(
panic!();
}
fn find_pair_to_simplify(transfers: &Vec<Edge>) -> Option<(usize, usize)> {
let l = transfers.len();
(0..l)
.flat_map(move |x| (0..l).map(move |y| (x, y)))
.find(|(i, j)| {
// We do not need matching capacity, but only then will we save
// a transfer.
let a = transfers[*i];
let b = transfers[*j];
*i != *j && a.to == b.from && a.token == b.token && a.capacity == b.capacity
})
}
fn simplify_transfers(mut transfers: Vec<Edge>) -> Vec<Edge> {
// We can simplify the transfers:
// If we have a transfer (A, B, T) and a transfer (B, C, T),
// We can always replace both by (A, C, T).
let mut simplifications = Vec::new();
for (i, a) in transfers.iter().enumerate() {
for (j, b) in transfers[i + 1..].iter().enumerate() {
// We do not need matching capacity, but only then will we save
// a transfer.
if a.to == b.from && a.token == b.token && a.capacity == b.capacity {
simplifications.push((i, i + j + 1));
}
}
}
for (i, j) in simplifications.iter().rev() {
transfers[*i].to = transfers[*j].to;
while let Some((i, j)) = find_pair_to_simplify(&transfers) {
transfers[i].to = transfers[j].to;
transfers.remove(j);
}
transfers
.into_iter()
.enumerate()
.flat_map(|(i, e)| {
if simplifications.iter().any(|(_, j)| i == *j) {
None
} else {
Some(e)
}
})
.collect::<Vec<_>>()
}
fn sort_transfers(transfers: Vec<Edge>) -> Vec<Edge> {