Commit 3871fca

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Merge pull request youngyangyang04#2289 from aFlyBird0/batch-1

改写两处Go代码,使其更符合Go习惯

2 parents 48692ef + 546d3b6 commit 3871fcaCopy full SHA for 3871fca

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problems
- 0213.打家劫舍II.md
- 1356.根据数字二进制下1的数目排序.md

2 files changed

+42

-43

lines changed

`‎problems/0213.打家劫舍II.md‎`

Lines changed: 25 additions & 19 deletions

Original file line number	Diff line number	Diff line change
`@@ -225,32 +225,38 @@ class Solution:`
`225`	`225`	`// 打家劫舍II 动态规划`
`226`	`226`	`// 时间复杂度O(n) 空间复杂度O(n)`
`227`	`227`	`func rob(nums []int) int {`
`228`		`- if len(nums) == 1 {`
`229`		`- return nums[0]`
	`228`	`+ // 如果长度为0或1,那么有没有环的限制都一样`
	`229`	`+ if len(nums) <= 1 {`
	`230`	`+ return robWithoutCircle(nums)`
`230`	`231`	`}`
`231`		`- if len(nums) == 2 {`
`232`		`- return max(nums[0], nums[1])`
`233`		`- }`
`234`		`-`
`235`		`- result1 := robRange(nums, 0)`
`236`		`- result2 := robRange(nums, 1)`
`237`		`- return max(result1, result2)`
	`232`	`+`
	`233`	`+ // 否则,去头或去尾,取最大`
	`234`	`+ res1 := robWithoutCircle(nums[:len(nums)-1])`
	`235`	`+ res2 := robWithoutCircle(nums[1:])`
	`236`	`+`
	`237`	`+ return max(res1, res2)`
`238`	`238`	`}`
`239`	`239`
`240`		`-// 偷盗指定的范围`
`241`		`-func robRange(nums []int, start int) int {`
	`240`	`+// 原始的打家劫舍版`
	`241`	`+func robWithoutCircle(nums []int) int {`
	`242`	`+ switch len(nums) {`
	`243`	`+ case 0: return 0`
	`244`	`+ case 1: return nums[0]`
	`245`	`+ }`
`242`	`246`	`dp := make([]int, len(nums))`
`243`		`- dp[1] = nums[start]`
`244`		`-`
`245`		`- for i := 2; i < len(nums); i++ {`
`246`		`- dp[i] = max(dp[i - 2] + nums[i - 1 + start], dp[i - 1])`
	`247`	`+ dp[0]=nums[0]`
	`248`	`+ dp[1] = max(nums[0], nums[1])`
	`249`	`+`
	`250`	`+ for i:=2; i<len(nums); i++ {`
	`251`	`+ dp[i] = max(dp[i-1], dp[i-2]+nums[i])`
`247`	`252`	`}`
`248`		`-`
`249`		`- return dp[len(nums) - 1]`
	`253`	`+`
	`254`	`+ return dp[len(nums)-1]`
	`255`	`+`
`250`	`256`	`}`
`251`	`257`
`252`		`-func max(a, b int) int {`
`253`		`- if a > b {`
	`258`	`+func max(a, b int) int {`
	`259`	`+ if a>b {`
`254`	`260`	`return a`
`255`	`261`	`}`
`256`	`262`	`return b`

`‎problems/1356.根据数字二进制下1的数目排序.md‎`

Lines changed: 17 additions & 24 deletions

Original file line number	Diff line number	Diff line change
`@@ -171,36 +171,29 @@ class Solution:`
`171`	`171`
`172`	`172`	```go
`173`	`173`	`func sortByBits(arr []int) []int {`
`174`		`- var tmp int`
`175`		`- for i := 0; i < len(arr); i++ {`
`176`		`- for j := i+1; j < len(arr); j++ {`
`177`		`- // 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`
`178`		`- if isCmp(arr[i], arr[j]) {`
`179`		`- tmp = arr[i]`
`180`		`- arr[i] = arr[j]`
`181`		`- arr[j] = tmp`
`182`		`- }`
`183`		`- }`
	`174`	`+ // 是否arr[i]<=arr[j]`
	`175`	`+ // 先比较1的数量,后比较值本身`
	`176`	`+ cmp := func(i, j int) bool {`
	`177`	`+ c1, c2 := bitCount(arr[i]), bitCount(arr[j])`
	`178`	`+ if c1 == c2 {`
	`179`	`+ return arr[i] <= arr[j]`
	`180`	`+ }`
	`181`	`+ return c1 <= c2`
`184`	`182`	`}`
`185`		`- return arr`
`186`		`-}`
`187`	`183`
`188`		`-func isCmp(a, b int) bool {`
`189`		`- bitA := bitCount(a)`
`190`		`- bitB := bitCount(b)`
`191`		`- if bitA == bitB {`
`192`		`- return a > b`
`193`		`- } else {`
`194`		`- return bitA > bitB`
`195`		`- }`
	`184`	`+ // 调用库函数`
	`185`	`+ // 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`
	`186`	`+ sort.Slice(arr, cmp)`
	`187`	`+`
	`188`	`+ return arr`
`196`	`189`	`}`
`197`	`190`
`198`		`-func bitCount(n int) int {`
`199`		`- count := 0`
`200`		`- for n != 0 {`
`201`		`- n &= (n-1) // 清除最低位的1`
	`191`	`+func bitCount(num int) (count int) {`
	`192`	`+ for num != 0 {`
	`193`	`+ num &= num-1 // 每次运算将最右侧的1变成0`
`202`	`194`	`count++`
`203`	`195`	`}`
	`196`	`+`
`204`	`197`	`return count`
`205`	`198`	`}`
`206`	`199`	```

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`‎problems/0213.打家劫舍II.md‎`

`‎problems/1356.根据数字二进制下1的数目排序.md‎`

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