From 495acd3709a07bef8de74f96d22dfa42c34ffbfa Mon Sep 17 00:00:00 2001
From: yigencong <yigencong@yahoo.com>
Date: Wed, 28 Feb 2024 13:03:35 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E6=B7=BB=E5=8A=A0=E8=AE=A1=E6=95=B0?=
 =?UTF-8?q?=E6=8E=92=E5=BA=8F?=
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---
 sort/count-sort.mjs | 60 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 sort/count-sort.mjs

diff --git a/sort/count-sort.mjs b/sort/count-sort.mjs
new file mode 100644
index 0000000..ae2dd68
--- /dev/null
+++ b/sort/count-sort.mjs
@@ -0,0 +1,60 @@
+/**
+ * @description 计数排序, 只能对大于零的整数排序
+ * @param {number[]} arr - 需要排序的数组
+ */
+export function countSort(arr) {
+  const len = arr.length;
+  const counts = []; // 用于计数的数组
+  // 遍历整个数组
+  for (let i = 0; i < len; i++) {
+    const el = arr[i];
+    counts[el] = counts[el] ? counts[el] + 1 : 1;
+  }
+  let index = 0;
+  for (let i = 0; i < counts.length; i++) {
+    let time = counts[i];
+    while (time) {
+      // 当桶子不为空时，遍历time次
+      arr[index++] = i;
+      time--;
+    }
+  }
+  return arr; // 返回与不反都可以，本身就是对原数组的操作
+}
+
+/**
+ * @description 修改后的计数排序，支持负数
+ * @param {number[]} arr - 要排序的整数数组
+ */
+export function countSort2(arr) {
+  // 先找出最大值和for
+  const n = arr.length;
+  let min = arr[0];
+  let max = arr[0];
+  for (let i = 0; i < n; i++) {
+    if (arr[i] > max) {
+      max = arr[i];
+    }
+    if (arr[i] < min) {
+      min = arr[i];
+    }
+  }
+  // 计算计数数组的大小
+  const size = max - min + 1;
+  const counts = new Array(size).fill(0);
+  // 遍历原数组把"值-min"作为计数数组的下标, 值-min能保证下标永 远不会小于零
+  for (let i = 0; i < n; i++) {
+    counts[arr[i] - min]++;
+  }
+  // 遍历counts数组， 累计前面的下下标值
+  for (let i = 1; i < size; i++) {
+    counts[i] += counts[i - 1];
+  }
+  const ret = [];// 排序后的新数组
+  // 现在数组的下表就是值，值就是下标
+  for (let i = n - 1; i >= 0; i--) {
+    counts[arr[i] - min]--; // 假设我们有三个数放入counts中，counts[0]=1,counts[1]=2,counts[2]=3,所以要先减1再做下标使用
+    ret[counts[arr[i] - min]] = arr[i];
+  }
+  return ret;
+}