FilesExpand file tree

 master

/

ExcelSheetColumnNumber .java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

executable file

·

50 lines (41 loc) · 1.08 KB

 master

/

ExcelSheetColumnNumber .java

Copy path

Top

File metadata and controls

• Code
• Blame

executable file

·

50 lines (41 loc) · 1.08 KB

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

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

E

'A' - 'A' = 0. 所以 char - 'A' + 1 = 题目里的对应数位。

26位运算和10位一样嘛，num += 每位的digit * Math.pow(26, 数位号)。

```

/*

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

A -> 1

B -> 2

C -> 3

...

Z -> 26

AA -> 27

AB -> 28

*/

public class Solution {//ABC -> 'A', 'B', 'C'

public int titleToNumber(String s) {//S = AA

int rst = 0;

char[] arr = s.toCharArray();

for (int i = 0; i < arr.length; i++) {//i = 0,1,2 // (char c : arr)

rst = rst * 26 + arr[i] - 'A' + 1;//rst =1, 26 + 1 = 27,

}

return rst;

}

}

//3.4.2016 recap

//digit * pow(26, digit position)

public class Solution {

public int titleToNumber(String s) {

if (s == null || s.length() == 0) {

return 0;

}

int num = 0;

for (int i = s.length() - 1; i >= 0; i--) {

int digit = s.charAt(i) - 'A' + 1;

num += digit * Math.pow(26, s.length() - i - 1);

}

return num;

}

}

```