Oct 5, 2023 · Sep 28, 2023 · Sep 28, 2023 · Oct 5, 2023
diff --git a/problems/0213.打家劫舍II.md b/problems/0213.打家劫舍II.md
diff --git a/problems/1356.根据数字二进制下1的数目排序.md b/problems/1356.根据数字二进制下1的数目排序.md
Original file line number	Diff line number	Diff line change
Expand Up		@@ -225,32 +225,38 @@ class Solution:
		// 打家劫舍II 动态规划
		// 时间复杂度O(n) 空间复杂度O(n)
		func rob(nums []int) int {
	if len(nums) == 1 {
	return nums[0]
	// 如果长度为0或1,那么有没有环的限制都一样
	if len(nums) <= 1 {
	return robWithoutCircle(nums)
		}
	if len(nums) == 2 {
	return max(nums[0], nums[1])
	}

	result1 := robRange(nums, 0)
	result2 := robRange(nums, 1)
	return max(result1, result2)

	// 否则,去头或去尾,取最大
	res1 := robWithoutCircle(nums[:len(nums)-1])
	res2 := robWithoutCircle(nums[1:])

	return max(res1, res2)
		}

	// 偷盗指定的范围
	func robRange(nums []int, start int) int {
	// 原始的打家劫舍版
	func robWithoutCircle(nums []int) int {
	switch len(nums) {
	case 0: return 0
	case 1: return nums[0]
	}
		dp := make([]int, len(nums))
	dp[1] = nums[start]

	for i := 2; i < len(nums); i++ {
	dp[i] = max(dp[i - 2] + nums[i - 1 + start], dp[i - 1])
	dp[0]=nums[0]
	dp[1] = max(nums[0], nums[1])

	for i:=2; i<len(nums); i++ {
	dp[i] = max(dp[i-1], dp[i-2]+nums[i])
		}

	return dp[len(nums) - 1]

	return dp[len(nums)-1]

		}

	func max(a, b int) int {
	if a > b {
	func max(a, b int) int {
	if a>b {
		return a
		}
		return b
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Original file line number	Diff line number	Diff line change
Expand Up		@@ -171,36 +171,29 @@ class Solution:

		```go
		func sortByBits(arr []int) []int {
	var tmp int
	for i := 0; i < len(arr); i++ {
	for j := i+1; j < len(arr); j++ {
	// 冒泡排序的手法,但是排序的规则从比大小变成了比位运算1的个数
	if isCmp(arr[i], arr[j]) {
	tmp = arr[i]
	arr[i] = arr[j]
	arr[j] = tmp
	}
	}
	// 是否arr[i]<=arr[j]
	// 先比较1的数量,后比较值本身
	cmp := func(i, j int) bool {
	c1, c2 := bitCount(arr[i]), bitCount(arr[j])
	if c1 == c2 {
	return arr[i] <= arr[j]
	}
	return c1 <= c2
		}
	return arr
	}

	func isCmp(a, b int) bool {
	bitA := bitCount(a)
	bitB := bitCount(b)
	if bitA == bitB {
	return a > b
	} else {
	return bitA > bitB
	}
	// 调用库函数
	// 第一个参数是待排序切片,第二个是第i位是否小于第j位的函数
	sort.Slice(arr, cmp)

	return arr
		}

	func bitCount(n int) int {
	count := 0
	for n != 0 {
	n &= (n-1) // 清除最低位的1
	func bitCount(num int) (count int) {
	for num != 0 {
	num &= num-1 // 每次运算将最右侧的1变成0
		count++
		}

		return count
		}
		```
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