Add problem 1323: Maximum 69 Number

src/lib.rs

@@ -537,6 +537,7 @@ pub mod problem_1304_find_n_unique_integers_sum_up_to_zero;
 pub mod problem_1310_xor_queries_of_a_subarray;
 pub mod problem_1315_sum_of_nodes_with_even_valued_grandparent;
 pub mod problem_1317_convert_integer_to_the_sum_of_two_no_zero_integers;
+pub mod problem_1323_maximum_69_number;
 pub mod problem_1324_print_words_vertically;
 pub mod problem_1325_delete_leaves_with_a_given_value;
 pub mod problem_1333_filter_restaurants_by_vegan_friendly_price_and_distance;

src/problem_1323_maximum_69_number/iterative.rs

@@ -0,0 +1,41 @@
+pub struct Solution;
+
+impl Solution {
+    pub fn maximum69_number(num: i32) -> i32 {
+        let mut result = 0;
+        let mut div = if num < 100 {
+            10
+        } else if num < 1000 {
+            100
+        } else {
+            1000
+        };
+        let mut num = num;
+        let mut ok = false;
+        while num != 0 {
+            let mut digit = num / div;
+            num %= div;
+            div /= 10;
+            if digit == 6 && !ok {
+                ok = true;
+                digit = 9;
+            }
+            result = result * 10 + digit;
+        }
+        result
+    }
+}
+
+impl super::Solution for Solution {
+    fn maximum69_number(num: i32) -> i32 {
+        Self::maximum69_number(num)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_1323_maximum_69_number/mod.rs

@@ -0,0 +1,18 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn maximum69_number(num: i32) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(9669, 9969), (9996, 9999), (9999, 9999)];
+
+        for (num, expected) in test_cases {
+            assert_eq!(S::maximum69_number(num), expected);
+        }
+    }
+}