Fix rust code

.github/workflows/rust.yml

@@ -7,16 +7,16 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: install rustc
+      - name: print rustc version
         run: |
-          sudo apt install rustc
-      - name: format
+          rustc --version
+      - name: check code formatting
         run: |
           cd rust
           cargo fmt -- --check
           RUSTFLAGS="-A unused" cargo clippy
           cargo clippy --tests
-      - name: compile
+      - name: compile and test
         run: |
           cd rust
           cargo test

rust/misc/binary_search.rs

@@ -1,8 +1,9 @@
 // invariant: f[lo] == false, f[hi] == true
-pub fn binary_search_first_true<F>(f: F, from_inclusive: i32, to_inclusive: i32) -> i32
-where
-    F: Fn(i32) -> bool,
-{
+pub fn binary_search_first_true<F: Fn(i32) -> bool>(
+    f: F,
+    from_inclusive: i32,
+    to_inclusive: i32,
+) -> i32 {
     let mut lo = from_inclusive - 1;
     let mut hi = to_inclusive + 1;
     while hi - lo > 1 {

rust/structures/mergeable_heap.rs

@@ -15,7 +15,7 @@ impl<V: PartialOrd> Heap<V> {
         }))
     }
 
-    fn merge(a: Option<Box<Heap<V>>>, b: Option<Box<Heap<V>>>) -> Option<Box<Heap<V>>> {
+    pub fn merge(a: Option<Box<Heap<V>>>, b: Option<Box<Heap<V>>>) -> Option<Box<Heap<V>>> {
         if a.is_none() {
             return b;
         }
@@ -34,13 +34,13 @@ impl<V: PartialOrd> Heap<V> {
         Some(ha)
     }
 
-    fn remove_min(heap: Option<Box<Heap<V>>>) -> (Option<Box<Heap<V>>>, V) {
-        let h = heap.unwrap();
-        (Self::merge(h.left, h.right), h.value)
+    pub fn insert(heap: Option<Box<Heap<V>>>, value: V) -> Option<Box<Heap<V>>> {
+        Self::merge(heap, Heap::new(value))
     }
 
-    fn add(heap: Option<Box<Heap<V>>>, value: V) -> Option<Box<Heap<V>>> {
-        Self::merge(heap, Heap::new(value))
+    pub fn remove_min(heap: Option<Box<Heap<V>>>) -> (Option<Box<Heap<V>>>, V) {
+        let h = heap.unwrap();
+        (Self::merge(h.left, h.right), h.value)
     }
 }
 
@@ -92,7 +92,7 @@ mod tests {
     }
 
     fn sort_with_heap(seq: &[u32]) -> Vec<u32> {
-        let mut heap = seq.iter().fold(None, |h, v| Heap::add(h, v));
+        let mut heap = seq.iter().fold(None, |h, v| Heap::insert(h, v));
         let mut heap_sorted_values = Vec::new();
         while heap.is_some() {
             let (updated_heap, min_value) = Heap::remove_min(heap);

rust/structures/mod.rs

@@ -2,3 +2,4 @@ pub mod disjoint_sets;
 pub mod fenwick_tree;
 pub mod mergeable_heap;
 pub mod persistent_tree;
+pub mod treap;