Commit e72a75d

committed

🐱(dynamic): 338. 比特位计数

补充解法二

1 parent 1614d48 commit e72a75dCopy full SHA for e72a75d

File tree

1 file changed

+44

-2

lines changed

docs/algorithm/dynamic
- README.md

1 file changed

+44

-2

lines changed

`‎docs/algorithm/dynamic/README.md‎`

Lines changed: 44 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -1316,12 +1316,11 @@ class Solution(object):`
`1316`	`1316`	`return res[amount]`
`1317`	`1317`	```
`1318`	`1318`
`1319`		`-`
`1320`	`1319`	`## 338. 比特位计数`
`1321`	`1320`
`1322`	`1321`	`[原题链接](https://leetcode-cn.com/problems/counting-bits/description/)`
`1323`	`1322`
`1324`		`-### 思路`
	`1323`	`+### 解法一`
`1325`	`1324`
`1326`	`1325`	`动态规划无疑了`
`1327`	`1326`
`@@ -1349,6 +1348,49 @@ class Solution(object):`
`1349`	`1348`	`return List1[:num+1]`
`1350`	`1349`	```
`1351`	`1350`
	`1351`	`+### 解法二`
	`1352`	`+`
	`1353`	`+奇偶数的二进制规律:`
	`1354`	`+`
	`1355`	`+- 奇数二进制数总比前一个偶数二进制数多 1 个 1(即最后 1 位)`
	`1356`	+- 偶数二进制数 `x` 中 1 的个数总等于 `x / 2` 中 1 的个数(除 2 等于右移 1 位,即抹去最后一位 0)
	`1357`	`+`
	`1358`	`+<!-- tabs:start -->`
	`1359`	`+`
	`1360`	`+c`
	`1361`	`+`
	`1362`	+```python
	`1363`	`+class Solution:`
	`1364`	`+ def countBits(self, num: int) -> List[int]:`
	`1365`	`+ ans = [0 for _ in range(num + 1)]`
	`1366`	`+ for i in range(num + 1):`
	`1367`	`+ if i % 2 == 0:`
	`1368`	`+ # 偶数`
	`1369`	`+ ans[i] = ans[i // 2]`
	`1370`	`+ else:`
	`1371`	`+ # 奇数`
	`1372`	`+ ans[i] = ans[i - 1] + 1`
	`1373`	`+ return ans`
	`1374`	+```
	`1375`	`+`
	`1376`	`+#### Go`
	`1377`	`+`
	`1378`	+```go
	`1379`	`+func countBits(num int) []int {`
	`1380`	`+ ans := make([]int, num + 1)`
	`1381`	`+ for i := 0; i <= num; i++ {`
	`1382`	`+ if i % 2 == 0 {`
	`1383`	`+ ans[i] = ans[i / 2]`
	`1384`	`+ } else {`
	`1385`	`+ ans[i] = ans[i - 1] + 1`
	`1386`	`+ }`
	`1387`	`+ }`
	`1388`	`+ return ans`
	`1389`	`+}`
	`1390`	+```
	`1391`	`+`
	`1392`	`+<!-- tabs:end -->`
	`1393`	`+`
`1352`	`1394`	`## 714. 买卖股票的最佳时机含手续费`
`1353`	`1395`
`1354`	`1396`	`[原题链接](https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-with-transaction-fee/)`

0 commit comments

Comments

(0)

Navigation Menu

Search code, repositories, users, issues, pull requests...

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Commit e72a75d

File tree

1 file changed

1 file changed

`‎docs/algorithm/dynamic/README.md‎`

0 commit comments