20240905 finished.

src/problem/mod.rs

@@ -225,4 +225,5 @@ mod p3127_make_a_square_with_the_same_color;
 mod p1450_number_of_students_doing_homework_at_a_given_time;
 mod p2024_maximize_the_confusion_of_an_exam;
 mod p2708_maximum_strength_of_a_group;
-mod p2860_happy_students;
+mod p2860_happy_students;
+mod p3174_clear_digits;

src/problem/p3174_clear_digits.rs

@@ -0,0 +1,50 @@
+/**
+ * [3174] Clear Digits
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn clear_digits(s: String) -> String {
+        let s: Vec<char> = s.chars().collect();
+        let mut mark = vec![true; s.len()];
+        
+        for (i, &c) in s.iter().enumerate() {
+            if !c.is_ascii_digit() {
+                continue;
+            }
+            
+            // 是数字
+            mark[i] = false;
+            let mut last = i - 1;
+
+            while !mark[last] {
+                last -= 1;
+            }
+            mark[last] = false;
+        }
+        
+        s.iter().enumerate().filter_map(|(i, &c)| {
+            if mark[i] {
+                Some(c)
+            } else { 
+                None
+            }
+        }).collect()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3174() {
+        assert_eq!("abc".to_owned(), Solution::clear_digits("abc".to_owned()));
+        assert_eq!("".to_owned(), Solution::clear_digits("cb34".to_owned()));
+    }
+}