Fix clippy warnings (TheAlgorithms#396)

Author: Arjun31415

src/data_structures/b_tree.rs

@@ -100,19 +100,18 @@ impl BTreeProps {
             self.insert_non_full(&mut node.children[u_index], key);
         }
     }
-
-    fn traverse_node<T: Ord + Debug>(&self, node: &Node<T>, depth: usize) {
+    fn traverse_node<T: Ord + Debug>(node: &Node<T>, depth: usize) {
         if node.is_leaf() {
             print!(" {0:{<1$}{2:?}{0:}<1$} ", "", depth, node.keys);
         } else {
             let _depth = depth + 1;
             for (index, key) in node.keys.iter().enumerate() {
-                self.traverse_node(&node.children[index], _depth);
+                Self::traverse_node(&node.children[index], _depth);
                 // Check https://doc.rust-lang.org/std/fmt/index.html
                 // And https://stackoverflow.com/a/35280799/2849127
                 print!("{0:{<1$}{2:?}{0:}<1$}", "", depth, key);
             }
-            self.traverse_node(node.children.last().unwrap(), _depth);
+            Self::traverse_node(node.children.last().unwrap(), _depth);
         }
     }
 }
@@ -141,7 +140,7 @@ where
     }
 
     pub fn traverse(&self) {
-        self.props.traverse_node(&self.root, 0);
+        BTreeProps::traverse_node(&self.root, 0);
         println!();
     }
 

src/data_structures/linked_list.rs

@@ -178,16 +178,16 @@ impl<T> LinkedList<T> {
         }
     }
 
-    pub fn get(&mut self, index: i32) -> Option<&T> {
-        self.get_ith_node(self.head, index)
+    pub fn get(&mut self, index: i32) -> Option<&'static T> {
+        Self::get_ith_node(self.head, index)
     }
 
-    fn get_ith_node(&mut self, node: Option<NonNull<Node<T>>>, index: i32) -> Option<&T> {
+    fn get_ith_node(node: Option<NonNull<Node<T>>>, index: i32) -> Option<&'static T> {
         match node {
             None => None,
             Some(next_ptr) => match index {
                 0 => Some(unsafe { &(*next_ptr.as_ptr()).val }),
-                _ => self.get_ith_node(unsafe { (*next_ptr.as_ptr()).next }, index - 1),
+                _ => Self::get_ith_node(unsafe { (*next_ptr.as_ptr()).next }, index - 1),
             },
         }
     }

src/dynamic_programming/edit_distance.rs

@@ -72,7 +72,7 @@ pub fn edit_distance_se(str_a: &str, str_b: &str) -> u32 {
             // c is distances[i][j-1] and s is distances[i-1][j-1] at the beginning of each round of iteration
             char_b = str_b[j - 1];
             c = min(
-                s + if char_a == char_b { 0 } else { 1 },
+                s + u32::from(char_a != char_b),
                 min(c + 1, distances[j] + 1),
             );
             // c is updated to distances[i][j], and will thus become distances[i][j-1] for the next cell

src/general/huffman_encoding.rs

@@ -43,7 +43,6 @@ impl<T> Ord for HuffmanNode<T> {
 impl<T: Clone + Copy + Ord> HuffmanNode<T> {
     /// Turn the tree into the map that can be used in encoding
     pub fn get_alphabet(
-        &self,
         height: u32,
         path: u64,
         node: &HuffmanNode<T>,
@@ -60,8 +59,8 @@ impl<T: Clone + Copy + Ord> HuffmanNode<T> {
                 );
             }
             None => {
-                self.get_alphabet(height + 1, path, node.left.as_ref().unwrap(), map);
-                self.get_alphabet(
+                Self::get_alphabet(height + 1, path, node.left.as_ref().unwrap(), map);
+                Self::get_alphabet(
                     height + 1,
                     path | (1 << height),
                     node.right.as_ref().unwrap(),
@@ -103,7 +102,7 @@ impl<T: Clone + Copy + Ord> HuffmanDictionary<T> {
             });
         }
         let root = queue.pop().unwrap();
-        root.get_alphabet(0, 0, &root, &mut alph);
+        HuffmanNode::get_alphabet(0, 0, &root, &mut alph);
         HuffmanDictionary {
             alphabet: alph,
             root,

src/graph/floyd_warshall.rs

@@ -30,7 +30,7 @@ pub fn floyd_warshall<V: Ord + Copy, E: Ord + Copy + Add<Output = E>>(
             });
         }
     }
-    let keys = map.iter().map(|(k, _)| *k).collect::<Vec<_>>();
+    let keys = map.keys().copied().collect::<Vec<_>>();
     for &k in &keys {
         for &i in &keys {
             if map[&i].get(&k).is_none() {
@@ -49,9 +49,7 @@ pub fn floyd_warshall<V: Ord + Copy, E: Ord + Copy + Add<Output = E>>(
                 match entry_i_j {
                     Some(&e) => {
                         if e > entry_i_k + entry_k_j {
-                            map.entry(i)
-                                .or_insert(BTreeMap::new())
-                                .insert(j, entry_i_k + entry_k_j);
+                            map.entry(i).or_default().insert(j, entry_i_k + entry_k_j);
                         }
                     }
                     None => {

src/graph/prufer_code.rs

@@ -33,7 +33,7 @@ pub fn prufer_encode<V: Ord + Copy>(tree: &Graph<V>) -> Vec<V> {
 
 #[inline]
 fn add_directed_edge<V: Ord + Copy>(tree: &mut Graph<V>, a: V, b: V) {
-    tree.entry(a).or_insert(vec![]).push(b);
+    tree.entry(a).or_default().push(b);
 }
 
 #[inline]