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401. 二进制手表 Binary Watch

时间:2017-01-11 07:44:46      阅读:321      评论:0      收藏:0      [点我收藏+]

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A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59).

Each LED represents a zero or one, with the least significant bit on the right.

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For example, the above binary watch reads "3:25".

Given a non-negative integer n which represents the number of LEDs that are currently on, return all possible times the watch could represent.

Example:

Input: n = 1
Return: ["1:00", "2:00", "4:00", "8:00", "0:01", "0:02", "0:04", "0:08", "0:16", "0:32"]

Note:

  • The order of output does not matter.
  • The hour must not contain a leading zero, for example "01:00" is not valid, it should be "1:00".
  • The minute must be consist of two digits and may contain a leading zero, for example "10:2" is not valid, it should be "10:02".

二进制手表上的数字有一个特点:转换成二进制后,只有1位的数字为1
例如: 2=10
            4=100
            8=1000
可以利用这一特性进行解题
  1. static public List<string> ReadBinaryWatch(int num) {
  2. List<string> list = new List<string>();
  3. string s = "";
  4. for (int i = 0; i < 12; i++) {
  5. for (int j = 0; j < 60; j++) {
  6. if (BitCount(i) + BitCount(j) == num) {
  7. list.Add(i.ToString() + ":" + NumberToString(j));
  8. }
  9. }
  10. }
  11. return list;
  12. }
  13. static public int BitCount(int number) {
  14. int sum = 0;
  15. while (number > 0) {
  16. if ((number & 1) == 1) {
  17. sum++;
  18. }
  19. number >>= 1;
  20. }
  21. return sum;
  22. }
  23. static public string NumberToString(int number) {
  24. string s = number.ToString();
  25. return s.PadLeft(2, ‘0‘);
  26. }





401. 二进制手表 Binary Watch

标签:back   技术   rtos   and   time   image   技术分享   rto   each   

原文地址:http://www.cnblogs.com/xiejunzhao/p/9a2a5a9e740619d04df1af25c93e6204.html

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