Add problem 1592: Rearrange Spaces Between Words

src/lib.rs

@@ -1303,6 +1303,7 @@ pub mod problem_1578_minimum_time_to_make_rope_colorful;
 pub mod problem_1582_special_positions_in_a_binary_matrix;
 pub mod problem_1588_sum_of_all_odd_length_subarrays;
 pub mod problem_1590_make_sum_divisible_by_p;
+pub mod problem_1592_rearrange_spaces_between_words;
 pub mod problem_1593_split_a_string_into_the_max_number_of_unique_substrings;
 pub mod problem_1594_maximum_non_negative_product_in_a_matrix;
 pub mod problem_1598_crawler_log_folder;

src/problem_1592_rearrange_spaces_between_words/iterative.rs

@@ -0,0 +1,80 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+use std::iter;
+
+impl Solution {
+    fn calculate_spaces_between_words(text: &[u8]) -> usize {
+        let mut words = 0;
+        let mut spaces = 0;
+        let mut is_space = true;
+
+        for &c in text {
+            let new_is_space = c == b' ';
+
+            spaces += usize::from(new_is_space);
+            words += usize::from(is_space && !new_is_space);
+            is_space = new_is_space;
+        }
+
+        if words < 2 {
+            0
+        } else {
+            spaces / (words - 1)
+        }
+    }
+
+    pub fn reorder_spaces(text: String) -> String {
+        let text = text.as_bytes();
+        let separator = iter::repeat(b' ').take(Self::calculate_spaces_between_words(text));
+        let mut result = Vec::with_capacity(text.len());
+        let mut word_start = None;
+
+        for (i, &c) in text.iter().enumerate() {
+            if c == b' ' {
+                if let Some(start) = word_start {
+                    word_start = None;
+
+                    if !result.is_empty() {
+                        result.extend(separator.clone());
+                    }
+
+                    result.extend(&text[start..i]);
+                }
+            } else if word_start.is_none() {
+                word_start = Some(i);
+            }
+        }
+
+        if let Some(start) = word_start {
+            if !result.is_empty() {
+                result.extend(separator);
+            }
+
+            result.extend(&text[start..]);
+        }
+
+        let missing = text.len() - result.len();
+
+        result.extend(iter::repeat(b' ').take(missing));
+
+        String::from_utf8(result).unwrap()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn reorder_spaces(text: String) -> String {
+        Self::reorder_spaces(text)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_1592_rearrange_spaces_between_words/mod.rs

@@ -0,0 +1,22 @@
+pub mod iterative;
+
+pub trait Solution {
+    fn reorder_spaces(text: String) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            ("  this   is  a sentence ", "this   is   a   sentence"),
+            (" practice   makes   perfect", "practice   makes   perfect "),
+            ("a", "a"),
+        ];
+
+        for (text, expected) in test_cases {
+            assert_eq!(S::reorder_spaces(text.to_string()), expected);
+        }
+    }
+}