From fcffdacfcb11752743994456125d99b00d5634f1 Mon Sep 17 00:00:00 2001
From: Miles <milesmao233@gmail.com>
Date: Thu, 10 Oct 2019 17:40:13 +0800
Subject: [PATCH] add javascript bucketSort

---
 javascript/13_sorts/bucketSort.js | 70 +++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 javascript/13_sorts/bucketSort.js

diff --git a/javascript/13_sorts/bucketSort.js b/javascript/13_sorts/bucketSort.js
new file mode 100644
index 0000000..d53d1b5
--- /dev/null
+++ b/javascript/13_sorts/bucketSort.js
@@ -0,0 +1,70 @@
+// 思路：
+// 将数组中的数据，按桶进行划分，将相邻的数据划分在同一个桶中
+// 每个桶用插入排序算法（或者快速排序）进行排序
+// 最后整合每个桶中的数据
+
+function bucketSort(array, bucketSize = 5) {
+    if (array.length < 2) {
+        return array
+    }
+    const buckets = createBuckets(array, bucketSize)
+    return sortBuckets(buckets)
+}
+
+function createBuckets(array, bucketSize) {
+    let minValue = array[0]
+    let maxValue = array[0]
+    // 遍历数组，找到数组最小值与数组最大值
+    for (let i = 1; i < array.length; i++) {
+        if (array[i] < minValue) {
+            minValue = array[i]
+        } else if (array[i] > maxValue) {
+            maxValue = array[i]
+        }
+    }
+    // 根据最小值、最大值、桶的大小，计算得到桶的个数
+    const bucketCount = Math.floor((maxValue - minValue) / bucketSize) + 1
+    // 建立一个二维数组，将桶放入buckets中
+    const buckets = []
+    for (let i = 0; i < bucketCount; i++) {
+        buckets[i] = []
+    }
+    // 计算每一个值应该放在哪一个桶中
+    for (let i = 0; i < array.length; i++) {
+        const bucketIndex = Math.floor((array[i] - minValue) / bucketSize)
+        buckets[bucketIndex].push(array[i])
+    }
+    return buckets
+}
+
+function sortBuckets(buckets) {
+    const sortedArray = []
+    for (let i = 0; i < buckets.length; i++) {
+        if (buckets[i] != null) {
+            insertionSort(buckets[i])
+            sortedArray.push(...buckets[i])
+        }
+    }
+    return sortedArray
+}
+
+// 插入排序
+function insertionSort(array) {
+    const { length } = array
+    if (length <= 1) return
+
+    for (let i = 1; i < length; i++) {
+        let value = array[i]
+        let j = i - 1
+
+        while (j >= 0) {
+            if (array[j] > value) {
+                array[j + 1] = array[j] // 移动
+                j--
+            } else {
+                break
+            }
+        }
+        array[j + 1] = value // 插入数据
+    }
+}