Add problem 2844: Minimum Operations to Make a Special Number

Author: EFanZh

src/lib.rs

@@ -1988,6 +1988,7 @@ pub mod problem_2833_furthest_point_from_origin;
 pub mod problem_2839_check_if_strings_can_be_made_equal_with_operations_i;
 pub mod problem_2840_check_if_strings_can_be_made_equal_with_operations_ii;
 pub mod problem_2841_maximum_sum_of_almost_unique_subarray;
+pub mod problem_2844_minimum_operations_to_make_a_special_number;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2844_minimum_operations_to_make_a_special_number/greedy.rs

@@ -0,0 +1,42 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn minimum_operations(num: String) -> i32 {
+        let mut iter_1 = num.bytes().rev();
+
+        let mut result = iter_1.position(|d| d == b'0').map_or(num.len(), |i| {
+            iter_1
+                .position(|d| matches!(d, b'5' | b'0'))
+                .map_or(num.len() - 1, |j| i + j)
+        });
+
+        iter_1 = num.bytes().rev();
+
+        if let Some(operations) = iter_1
+            .position(|d| d == b'5')
+            .and_then(|i| iter_1.position(|d| matches!(d, b'2' | b'7')).map(|j| i + j))
+        {
+            result = result.min(operations);
+        }
+
+        result as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn minimum_operations(num: String) -> i32 {
+        Self::minimum_operations(num)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2844_minimum_operations_to_make_a_special_number/mod.rs

@@ -0,0 +1,18 @@
+pub mod greedy;
+
+pub trait Solution {
+    fn minimum_operations(num: String) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [("2245047", 2), ("2908305", 3), ("10", 1)];
+
+        for (num, expected) in test_cases {
+            assert_eq!(S::minimum_operations(num.to_string()), expected);
+        }
+    }
+}