20241024 finished.

src/problem/p2376_count_special_integers.rs

@@ -1,17 +1,18 @@
-
 /**
  * [2376] Count Special Integers
  */
 pub struct Solution {}
 
-
 // submission codes start here
 use std::collections::HashMap;
 
 impl Solution {
     pub fn count_special_numbers(n: i32) -> i32 {
-
-        let n: Vec<i32> = n.to_string().chars().map(|c| c.to_digit(10).unwrap() as i32).collect();
+        let n: Vec<i32> = n
+            .to_string()
+            .chars()
+            .map(|c| c.to_digit(10).unwrap() as i32)
+            .collect();
 
         let mut result = 0;
         let mut candidate = 9;
@@ -23,44 +24,42 @@ impl Solution {
         }
 
         let mut memory: HashMap<i32, i32> = HashMap::new();
-        
+
         result += Self::dp(0, false, &mut memory, &n);
 
         result
     }
-   
+
     // mask 表示前缀中使用过的数字 使用二进制表示
     // prefix_smaller 当前的前缀是否小于n的前缀
-    fn dp(mask: i32, prefix_smaller: bool, memory: &mut HashMap<i32, i32>, number: &Vec<i32>) -> i32 {
+    fn dp(
+        mask: i32,
+        prefix_smaller: bool,
+        memory: &mut HashMap<i32, i32>,
+        number: &Vec<i32>,
+    ) -> i32 {
         let used_bits = mask.count_ones() as usize;
         if used_bits == number.len() {
             return 1;
         }
 
-        let key = mask * 2 + if prefix_smaller {
-            1
-        } else {
-            0
-        };
-        
+        let key = mask * 2 + if prefix_smaller { 1 } else { 0 };
+
         if !memory.contains_key(&key) {
             let mut result = 0;
 
-            let lower_bound = if mask == 0 {
-                1
-            } else {
-                0
-            };
+            let lower_bound = if mask == 0 { 1 } else { 0 };
 
-            let upper_bound = if prefix_smaller {
-                9
-            } else {
-                number[used_bits]
-            };
+            let upper_bound = if prefix_smaller { 9 } else { number[used_bits] };
 
             for i in lower_bound..=upper_bound {
                 if mask >> i & 1 == 0 {
-                    result += Self::dp(mask | 1 << i, prefix_smaller || i < upper_bound, memory, number);
+                    result += Self::dp(
+                        mask | 1 << i,
+                        prefix_smaller || i < upper_bound,
+                        memory,
+                        number,
+                    );
                 }
             }