diff --git a/codes/ruby/chapter_sorting/bubble_sort.rb b/codes/ruby/chapter_sorting/bubble_sort.rb new file mode 100644 index 000000000..c97764267 --- /dev/null +++ b/codes/ruby/chapter_sorting/bubble_sort.rb @@ -0,0 +1,51 @@ +=begin +File: bubble_sort.rb +Created Time: 2024-05-02 +Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com) +=end + +### 冒泡排序 ### +def bubble_sort(nums) + n = nums.length + # 外循环:未排序区间为 [0, i] + for i in (n - 1).downto(1) + # 内循环:将未排序区间 [0, i] 中的最大元素交换至该区间的最右端 + for j in 0...i + if nums[j] > nums[j + 1] + # 交换 nums[j] 与 nums[j + 1] + nums[j], nums[j + 1] = nums[j + 1], nums[j] + end + end + end +end + +### 冒泡排序(标志优化)### +def bubble_sort_with_flag(nums) + n = nums.length + # 外循环:未排序区间为 [0, i] + for i in (n - 1).downto(1) + flag = false # 初始化标志位 + + # 内循环:将未排序区间 [0, i] 中的最大元素交换至该区间的最右端 + for j in 0...i + if nums[j] > nums[j + 1] + # 交换 nums[j] 与 nums[j + 1] + nums[j], nums[j + 1] = nums[j + 1], nums[j] + flag = true # 记录交换元素 + end + end + + break unless flag # 此轮“冒泡”未交换任何元素,直接跳出 + end +end + +### Driver Code ### +if __FILE__ == $0 + nums = [4, 1, 3, 1, 5, 2] + bubble_sort(nums) + puts "冒泡排序完成后 nums = #{nums}" + + nums1 = [4, 1, 3, 1, 5, 2] + bubble_sort_with_flag(nums1) + puts "冒泡排序完成后 nums = #{nums1}" +end diff --git a/codes/ruby/chapter_sorting/counting_sort.rb b/codes/ruby/chapter_sorting/counting_sort.rb new file mode 100644 index 000000000..ca86944e4 --- /dev/null +++ b/codes/ruby/chapter_sorting/counting_sort.rb @@ -0,0 +1,62 @@ +=begin +File: counting_sort.rb +Created Time: 2024-05-02 +Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com) +=end + +### 计数排序 ### +def counting_sort_naive(nums) + # 简单实现,无法用于排序对象 + # 1. 统计数组最大元素 m + m = 0 + nums.each { |num| m = [m, num].max } + # 2. 统计各数字的出现次数 + # counter[num] 代表 num 的出现次数 + counter = Array.new(m + 1, 0) + nums.each { |num| counter[num] += 1 } + # 3. 遍历 counter ,将各元素填入原数组 nums + i = 0 + for num in 0...(m + 1) + (0...counter[num]).each do + nums[i] = num + i += 1 + end + end +end + +### 计数排序 ### +def counting_sort(nums) + # 完整实现,可排序对象,并且是稳定排序 + # 1. 统计数组最大元素 m + m = nums.max + # 2. 统计各数字的出现次数 + # counter[num] 代表 num 的出现次数 + counter = Array.new(m + 1, 0) + nums.each { |num| counter[num] += 1 } + # 3. 求 counter 的前缀和,将“出现次数”转换为“尾索引” + # 即 counter[num]-1 是 num 在 res 中最后一次出现的索引 + (0...m).each { |i| counter[i + 1] += counter[i] } + # 4. 倒序遍历 nums, 将各元素填入结果数组 res + # 初始化数组 res 用于记录结果 + n = nums.length + res = Array.new(n, 0) + (n - 1).downto(0).each do |i| + num = nums[i] + res[counter[num] - 1] = num # 将 num 放置到对应索引处 + counter[num] -= 1 # 令前缀和自减 1 ,得到下次放置 num 的索引 + end + # 使用结果数组 res 覆盖原数组 nums + (0...n).each { |i| nums[i] = res[i] } +end + +### Driver Code ### +if __FILE__ == $0 + nums = [1, 0, 1, 2, 0, 4, 0, 2, 2, 4] + + counting_sort_naive(nums) + puts "计数排序(无法排序对象)完成后 nums = #{nums}" + + nums1 = [1, 0, 1, 2, 0, 4, 0, 2, 2, 4] + counting_sort(nums1) + puts "计数排序完成后 nums1 = #{nums1}" +end diff --git a/codes/ruby/chapter_sorting/radix_sort.rb b/codes/ruby/chapter_sorting/radix_sort.rb new file mode 100644 index 000000000..d5611ee74 --- /dev/null +++ b/codes/ruby/chapter_sorting/radix_sort.rb @@ -0,0 +1,70 @@ +=begin +File: radix_sort.rb +Created Time: 2024-05-03 +Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com) +=end + +### 获取元素 num 的第 k 位,其中 exp = 10^(k-1) ### +def digit(num, exp) + # 转入 exp 而非 k 可以避免在此重复执行昂贵的次方计算 + (num / exp) % 10 +end + +### 计数排序(根据 nums 第 k 位排序)### +def counting_sort_digit(nums, exp) + # 十进制的位范围为 0~9 ,因此需要长度为 10 的桶数组 + counter = Array.new(10, 0) + n = nums.length + # 统计 0~9 各数字的出现次数 + for i in 0...n + d = digit(nums[i], exp) # 获取 nums[i] 第 k 位,记为 d + counter[d] += 1 # 统计数字 d 的出现次数 + end + # 求前缀和,将“出现个数”转换为“数组索引” + (1...10).each { |i| counter[i] += counter[i - 1] } + # 倒序遍历,根据桶内统计结果,将各元素填入 res + res = Array.new(n, 0) + for i in (n - 1).downto(0) + d = digit(nums[i], exp) + j = counter[d] - 1 # 获取 d 在数组中的索引 j + res[j] = nums[i] # 将当前元素填入索引 j + counter[d] -= 1 # 将 d 的数量减 1 + end + # 使用结果覆盖原数组 nums + (0...n).each { |i| nums[i] = res[i] } +end + +### 基数排序 ### +def radix_sort(nums) + # 获取数组的最大元素,用于判断最大位数 + m = nums.max + # 按照从低位到高位的顺序遍历 + exp = 1 + while exp <= m + # 对数组元素的第 k 位执行计数排序 + # k = 1 -> exp = 1 + # k = 2 -> exp = 10 + # 即 exp = 10^(k-1) + counting_sort_digit(nums, exp) + exp *= 10 + end +end + +### Driver Code ### +if __FILE__ == $0 + # 基数排序 + nums = [ + 10546151, + 35663510, + 42865989, + 34862445, + 81883077, + 88906420, + 72429244, + 30524779, + 82060337, + 63832996, + ] + radix_sort(nums) + puts "基数排序完成后 nums = #{nums}" +end diff --git a/codes/ruby/chapter_sorting/selection_sort.rb b/codes/ruby/chapter_sorting/selection_sort.rb new file mode 100644 index 000000000..79fe73eea --- /dev/null +++ b/codes/ruby/chapter_sorting/selection_sort.rb @@ -0,0 +1,29 @@ +=begin +File: selection_sort.rb +Created Time: 2024-05-03 +Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com) +=end + +### 选择排序 ### +def selection_sort(nums) + n = nums.length + # 外循环:未排序区间为 [i, n-1] + for i in 0...(n - 1) + # 内循环:找到未排序区间内的最小元素 + k = i + for j in (i + 1)...n + if nums[j] < nums[k] + k = j # 记录最小元素的索引 + end + end + # 将该最小元素与未排序区间的首个元素交换 + nums[i], nums[k] = nums[k], nums[i] + end +end + +### Driver Code ### +if __FILE__ == $0 + nums = [4, 1, 3, 1, 5, 2] + selection_sort(nums) + puts "选择排序完成后 nums = #{nums}" +end