Add problem 3106: Lexicographically Smallest String After Operations With Constraint

Author: EFanZh

src/lib.rs

@@ -2089,6 +2089,7 @@ pub mod problem_3097_shortest_subarray_with_or_at_least_k_ii;
 pub mod problem_3099_harshad_number;
 pub mod problem_3101_count_alternating_subarrays;
 pub mod problem_3105_longest_strictly_increasing_or_strictly_decreasing_subarray;
+pub mod problem_3106_lexicographically_smallest_string_after_operations_with_constraint;
 pub mod problem_3350_adjacent_increasing_subarrays_detection_ii;
 
 #[cfg(test)]

src/problem_3106_lexicographically_smallest_string_after_operations_with_constraint/greedy.rs

@@ -0,0 +1,41 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn get_smallest_string(s: String, k: i32) -> String {
+        let mut s = s.into_bytes();
+        let mut k = k.cast_unsigned();
+
+        for c in &mut s {
+            let diff = u32::from(u8::min(*c - b'a', b'z' + 1 - *c));
+
+            if diff <= k {
+                *c = b'a';
+                k -= diff;
+            } else {
+                *c -= k as u8;
+
+                break;
+            }
+        }
+
+        String::from_utf8(s).unwrap()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn get_smallest_string(s: String, k: i32) -> String {
+        Self::get_smallest_string(s, k)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_3106_lexicographically_smallest_string_after_operations_with_constraint/mod.rs

@@ -0,0 +1,18 @@
+pub mod greedy;
+
+pub trait Solution {
+    fn get_smallest_string(s: String, k: i32) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [(("zbbz", 3), "aaaz"), (("xaxcd", 4), "aawcd"), (("lol", 0), "lol")];
+
+        for ((s, k), expected) in test_cases {
+            assert_eq!(S::get_smallest_string(s.to_string(), k), expected);
+        }
+    }
+}