FilesExpand file tree

 master

/

NumberOfDigitOne.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

32 lines (27 loc) · 814 Bytes

 master

/

NumberOfDigitOne.java

Copy path

Top

File metadata and controls

• Code
• Blame

32 lines (27 loc) · 814 Bytes

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

public class NumberOfDigitOne {

/**

* 下面要注意所有局部变量都是long的，因为factor*10可能会溢出

*/

public int countDigitOne(int n) {

long count = 0, factor = 1;

long low = 0, cur = 0, high = 0;

while (n / factor > 0) {

low = n % factor;

cur = (n / factor) % 10;

high = n / (factor * 10);

switch ((int) cur) {

case 0:

count += high * factor;

break;

case 1:

count += high * factor + low + 1;

break;

default:

count += (high + 1) * factor;

break;

}

factor *= 10;

}

return (int) count;

}

}