Add problem 1963: Minimum Number of Swaps to Make the String Balanced

src/lib.rs

@@ -1362,6 +1362,7 @@ pub mod problem_1952_three_divisors;
 pub mod problem_1957_delete_characters_to_make_fancy_string;
 pub mod problem_1961_check_if_string_is_a_prefix_of_array;
 pub mod problem_1962_remove_stones_to_minimize_the_total;
+pub mod problem_1963_minimum_number_of_swaps_to_make_the_string_balanced;
 pub mod problem_1967_number_of_strings_that_appear_as_substrings_in_word;
 pub mod problem_1968_array_with_elements_not_equal_to_average_of_neighbors;
 

src/problem_1963_minimum_number_of_swaps_to_make_the_string_balanced/iterative.rs

@@ -0,0 +1,37 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    pub fn min_swaps(s: String) -> i32 {
+        let mut stack = 0_u32;
+
+        for c in s.into_bytes() {
+            stack = stack.wrapping_add(if c == b'[' {
+                1
+            } else if stack == 0 {
+                0
+            } else {
+                u32::MAX
+            });
+        }
+
+        ((stack + 1) / 2) as _
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn min_swaps(s: String) -> i32 {
+        Self::min_swaps(s)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_1963_minimum_number_of_swaps_to_make_the_string_balanced/mod.rs

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