Apply cargo clippy --fix

Author: martwz

src/leetcode/interview/amazon/reorder_log_files.rs

@@ -6,7 +6,7 @@ impl Solution {
         let mut digit_logs = vec![];
 
         for log in logs {
-            let chunks = log.split(" ").map(|s| s.to_string()).collect::<Vec<String>>();
+            let chunks = log.split(' ').map(|s| s.to_string()).collect::<Vec<String>>();
             let id = chunks[0].clone();
             let msg = &chunks[1..];
             let kind = {
@@ -27,7 +27,7 @@ impl Solution {
         letter_logs.sort_by(|a, b| {
             let (id_a, msg_a) = a;
             let (id_b, msg_b) = b;
-            msg_a.cmp(&msg_b).then_with(|| id_a.cmp(&id_b))
+            msg_a.cmp(msg_b).then_with(|| id_a.cmp(id_b))
         });
 
         letter_logs.into_iter().map(|(id, msg)| format!("{} {}", id, msg)).into_iter().chain(digit_logs).collect()

src/leetcode/interview/robinhood/alert_names.rs

@@ -36,7 +36,7 @@ impl Solution {
             }
         });
 
-        let mut ans = ans.iter().map(|f| f.clone()).collect::<Vec<String>>();
+        let mut ans = ans.iter().cloned().collect::<Vec<String>>();
         ans.sort_unstable();
         ans
     }

src/leetcode/problem/climb_stairs.rs

@@ -10,7 +10,7 @@ impl Solution {
             for i in 4..=n as usize {
                 dp[i] = dp[i - 1] + dp[i - 2];
             }
-            return dp[n as usize];
+            dp[n as usize]
         }
 }
 

src/leetcode/problem/exist.rs

@@ -2,7 +2,7 @@ use std::collections::{HashSet, VecDeque};
 
 impl Solution {
     pub fn exist(board: Vec<Vec<char>>, word: String) -> bool {
-        if word.len() == 0 {
+        if word.is_empty() {
             return true;
         }
 
@@ -30,7 +30,7 @@ impl Solution {
             seen[i as usize][j as usize] = 1;
             let dirs = vec![(0, 1), (0, -1), (1, 0), (-1, 0)];
             for dir in dirs.iter() {
-                let pos = (i + dir.0, j + dir.1);
+                let _pos = (i + dir.0, j + dir.1);
                 dfs(board, word, idx + 1, (i + dir.0, j + dir.1), seen, ans);
             }
             seen[i as usize][j as usize] = 0;

src/leetcode/problem/implement_trie_prefix_tree.rs

@@ -22,16 +22,11 @@ impl Trie {
     fn insert(&mut self, word: String) {
         let mut current = &mut self.root;
         for c in word.chars() {
-            if !current.children.contains_key(&c) {
-                current.children.insert(
-                    c,
-                    CharNode {
+            current.children.entry(c).or_insert(CharNode {
                         char: c,
                         is_word: false,
                         children: HashMap::new(),
-                    },
-                );
-            }
+                    });
             current = current.children.get_mut(&c).unwrap();
         }
         current.is_word = true;

src/leetcode/problem/solve_n_queens.rs

@@ -31,16 +31,16 @@ impl Solution {
                 }
             }
 
-            return true;
+            true
         }
 
         let mut ans: Vec<Vec<Vec<i32>>> = vec![];
         fn backtracking(ans: &mut Vec<Vec<Vec<i32>>>, board: &mut Vec<Vec<i32>>, n: usize, placed: usize, i: usize, j: usize) {
             if placed == n {
                 ans.push(board.clone());
-                return;
+                
             } else if i == n {
-                return;
+                
             } else if j == n {
                 backtracking(ans, board, n, placed, i + 1, 0);
             } else {

src/leetcode/problem/total_n_queens.rs

@@ -31,16 +31,16 @@ impl Solution {
                 }
             }
 
-            return true;
+            true
         }
 
         let mut ans: Vec<Vec<Vec<i32>>> = vec![];
         fn backtracking(ans: &mut Vec<Vec<Vec<i32>>>, board: &mut Vec<Vec<i32>>, n: usize, placed: usize, i: usize, j: usize) {
             if placed == n {
                 ans.push(board.clone());
-                return;
+                
             } else if i == n {
-                return;
+                
             } else if j == n {
                 backtracking(ans, board, n, placed, i + 1, 0);
             } else {