A Binary Watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom repr Esent the minutes (0-59).
Each LED represents a zero or one and the least significant bit on the right.
For example, the above binary watch reads "3:25".
Given a non-negative integer n which represents the number of LEDs that is currently on, return all possible Tim Es 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" are not valid and it should be "1:00".
- The minute must be consist of both digits and may contain a leading zero, for example "10:2" are not valid, it should be "10 : 02 ".
The number on the binary watch has one feature: After converting to binary, only 1 digits are 1 For example: 2=10 4=100
8=1000
This feature can be used to solve problems
static public List<string> ReadBinaryWatch(int num) {
List<string> list = new List<string>();
string s = "";
for (int i = 0; i < 12; i++) {
for ( int J = 0 J < 60 ; J ++) {
if ( bitcount ( I ) + Span class= "Typ" >bitcount ( j Span class= "PLN" > == num ) {
list.Add(i.ToString() + ":" + NumberToString(j));
}
}
}
return list;
}
static public int BitCount(int number) {
int sum = 0;
while (number > 0) {
if ((number & 1) == 1) {
sum++;
}
number >>= 1;
}
return sum;
}
static public string NumberToString(int number) {
string s = number.ToString();
return s.PadLeft(2, ‘0‘);
}
From for notes (Wiz)
401. Binary Watches binary Watch