Merge pull request #1130 from i-vishi/dev

added quick sort, merge, counting sort in Rust

Sorting/BubbleSortPHP/bubblesort.php → Sorting/Bubble Sort/PHP/bubble-sort.php

@@ -25,4 +25,4 @@ function print_array($array) {
 print_array($array);
 bubble_sort($array);
 
-?>
+?>

Sorting/Counting Sort/Rust/counting-sort.rs

@@ -0,0 +1,63 @@
+/// Counting sort
+
+/// * `arr` - Collection of value to be sorted in place.
+
+/// * `min` - Lower bound of the integer range.
+
+/// * `max` - Upper bound of the integer range.
+
+/// * `key` - Function extracting key witn the integer range from elements.
+
+pub fn counting_sort<F, T>(arr: &mut [T], min: usize, max: usize, key: F)
+where
+    F: Fn(&T) -> usize,
+    T: Clone,
+{
+    let mut prefix_sums = {
+        // 1. Initialize the count array with default value 0.
+        let len = max - min;
+        let mut count_arr = Vec::with_capacity(len);
+        count_arr.resize(len, 0);
+
+        // 2. Scan elements to collect counts.
+        for value in arr.iter() {
+            count_arr[key(value)] += 1;
+        }
+
+        // 3. Calculate prefix sum.
+        count_arr
+            .into_iter()
+            .scan(0, |state, x| {
+                *state += x;
+                Some(*state - x)
+            })
+            .collect::<Vec<usize>>()
+    };
+
+    // 4. Use prefix sum as index position of output element.
+    for value in arr.to_vec().iter() {
+        let index = key(value);
+        arr[prefix_sums[index]] = value.clone();
+        prefix_sums[index] += 1;
+    }
+}
+
+#[cfg(test)]
+
+mod base {
+    use super::*;
+    fn counting_sort_(arr: &mut [i32]) {
+        counting_sort(arr, 1, 10, |int| *int as usize);
+    }
+    base_cases!(counting_sort_);
+}
+
+#[cfg(test)]
+
+mod stability {
+    use super::*;
+    fn counting_sort_(arr: &mut [(i32, i32)]) {
+        counting_sort(arr, 1, 10, |t| t.0 as usize);
+    }
+    stability_cases!(counting_sort_);
+}

Sorting/Merge Sort/Rust/merge-sort.rs

@@ -0,0 +1,55 @@
+fn merge<T: Copy + PartialOrd>(x1: &[T], x2: &[T], y: &mut [T]) {
+    assert_eq!(x1.len() + x2.len(), y.len());
+    let mut i = 0;
+    let mut j = 0;
+    let mut k = 0;
+    while i < x1.len() && j < x2.len() {
+        if x1[i] < x2[j] {
+            y[k] = x1[i];
+            k += 1;
+            i += 1;
+        } else {
+            y[k] = x2[j];
+            k += 1;
+            j += 1;
+        }
+    }
+    if i < x1.len() {
+        y[k..].copy_from_slice(&x1[i..]);
+    }
+    if j < x2.len() {
+        y[k..].copy_from_slice(&x2[j..]);
+    }
+}
+
+fn merge_sort<T: Copy + Ord>(x: &mut [T]) {
+	let n = x.len();
+	let m = n / 2;
+
+	if n <= 1 {
+		return;
+	}
+
+	merge_sort(&mut x[0..m]);
+	merge_sort(&mut x[m..n]);
+
+	let mut y: Vec<T> = x.to_vec();
+
+	merge(&x[0..m], &x[m..n], &mut y[..]);
+
+	x.copy_from_slice(&y);
+}
+
+fn main() {
+    println!("Sort numbers ascending");
+    let mut numbers = [4, 65, 2, -31, 0, 99, 2, 83, 782, 1];
+    println!("Before: {:?}", numbers);
+    merge_sort(&mut numbers);
+    println!("After:  {:?}\n", numbers);
+
+    println!("Sort strings alphabetically");
+    let mut strings = ["beach", "hotel", "airplane", "car", "house", "art"];
+    println!("Before: {:?}", strings);
+    merge_sort(&mut strings);
+    println!("After:  {:?}\n", strings);
+}

Sorting/quickSort/Rust/quick-sort.rs

@@ -0,0 +1,43 @@
+pub fn quick_sort<T: Ord>(arr: &mut [T]) {
+    let len = arr.len();
+    _quick_sort(arr, 0, (len - 1) as isize);
+}
+
+fn _quick_sort<T: Ord>(arr: &mut [T], low: isize, high: isize) {
+    if low < high {
+        let p = partition(arr, low, high);
+        _quick_sort(arr, low, p - 1);
+        _quick_sort(arr, p + 1, high);
+    }
+}
+
+fn partition<T: Ord>(arr: &mut [T], low: isize, high: isize) -> isize {
+    let pivot = high as usize;
+    let mut store_index = low - 1;
+    let mut last_index = high;
+
+    loop {
+        store_index += 1;
+        while arr[store_index as usize] < arr[pivot] {
+            store_index += 1;
+        }
+        last_index -= 1;
+        while last_index >= 0 && arr[last_index as usize] > arr[pivot] {
+            last_index -= 1;
+        }
+        if store_index >= last_index {
+            break;
+        } else {
+            arr.swap(store_index as usize, last_index as usize);
+        }
+    }
+    arr.swap(store_index as usize, pivot as usize);
+    store_index
+}
+fn main() {
+    println!("Sort numbers ascending");
+    let mut numbers = [4, 65, 2, -31, 0, 99, 2, 83, 782, 1];
+    println!("Before: {:?}", numbers);
+    quick_sort(&mut numbers);
+    println!("After:  {:?}\n", numbers);
+}